Tidal Pools And Water Changes

[Tommy Gun]

Honestly I don't mind at all. I openly admit my tank is overstocked though you are correct that I have taken special precautions and that I have bigger tanks to be set up.

Glad to hear that. Hopefully some of this info and ideas can help motivate you to get those bigger tanks set up because if you can have such a great tank right now, I can't wait to see that on a bigger scale!!!

Though as the sharks needed somewhere in the region of a 3 hour or more flight, it is likely to be some distance.

While it is certainly possible and I wouldn't doubt that, were they trying to save the sharks or something? I ask because the bull shark isn't really foreign to the Australian coast and perhaps they could have gone out and found their own within driving distance. Again, since I haven't seen the documentary, I am only speculating and not doubting what you are telling me(us) about it.

Indeed it could, though the fact they merely showed getting the container near the building and then throwing the sharks into a box and then into the tank makes me wonder where and how any acclimatisation would take place.

You are right, that would be pretty odd....I was just trying to be subjective, not argumentative.

But who has actually said that? I distinctly put in that bull sharks are somewhat varied in their environments but stated it agreed with the advice in many places that fish do not need the long 2-4 hour drip acclimatisation that many inverts do.

Apparently I assumed too much by thinking that you were trying to show evidence of skipping acclimation and how it can apply to us since I don't think many of us are keeping bull sharks. While I do agree with you that some advice can become excessive, I still think 2 hours is not that far out of the range of being appropriate for some fish and like you say, definitely not a bad idea for inverts.

I also don't really know how it can agree with advice on other fish since the bull shark looks to be a somewhat extreme exception. Additionally, based upon our conversations in the past and as you also mentioned, perhaps some fish are more likely to experience environments which change (or who travel between one environment which differs from another) and hence, may have evolved to deal with such changes....however I still those changes occur more slowly that it may have been implied

A simple UV on the inlet would stop those problems. I seem to recall pictures of a man living in South East Asia who had such a tank (around 1,900 gallons) which basically had almost no filtration but piped sea water straight in and straight back out.

Well, forgetting the fact that some people are adamant that UV is useless (not speaking of Lynden), I can see how this would afford protection against some disease and parasites, but not against pollution...which I realize might be a stretch in many areas of the world anyways....and of course, I also realize that the Kelly Tarlton's Antarctic Encounter and Underwater World uses a natural source of water. Again, just trying to be subjective. Trust me, if I had the opportunity to do that, you can be completely sure that I would have a 500+ gallon reef in my house right now.

But as I stated (and you would appear to agree) osmoregulation is an important part of the acclimatisation. Almost all innvertebrates are osmoconformists, so do not have any sort of buffer provided by kidneys and the such. I certainly agree that inverts do require long acclimatisation, but I do not believe fish need such lengthy periods.

I also agree and have been saying this since the day I joined the forum....the argument here is more centered on what constitutes "too lengthy" versus "just right". Like I said, I think that some advice boarders on being excessive, but doubt that acclimating fish for 2 to 4 hours is going to cause more harm than good. 8 to 10 hours, ok, but not 2 to 4 hours.

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In the spirit of debate and going against any fabric in which we are trying to see who is right or wrong, I thought it would be interesting to get some other perspectives on the acclimation 'presentation' that you can see by clicking HERE. In short, if you scroll through the slides, they basically say that you should always drip acclimate any fish you buy from them (I might add that they are saltwater fish - it is saltwaterfish.com afterall), but that no one should acclimate corals other than to float to match water temp and then release. For the fish and other inverts, if I did the math right, I think they are suggesting an acclimation time of at least an hour and a half.

Just to be clear, I realize that much of the information on a store can convincingly be argued to be 'tainted' because they are trying to make money and could 'tailor' advice in order to optimize that so I am only bringing this up for discussion and not to open the door for bashing that website or anything. ok?

 

[andywg]

I also don't really know how it can agree with advice on other fish since the bull shark looks to be a somewhat extreme exception.

Because I have often seen on UK marine forums that half an hour is more than enough for fish (not inverts) and as such seeing "experts" performing zero acclimatisation would agree with that advice.

Additionally, based upon our conversations in the past and as you also mentioned, perhaps some fish are more likely to experience environments which change (or who travel between one environment which differs from another) and hence, may have evolved to deal with such changes....however I still those changes occur more slowly that it may have been implied

Swimming from one temperature of water across the thermocline to another where the difference is so great that shimmering occurs would not be all that slowly, surely.

Well, forgetting the fact that some people are adamant that UV is useless (not speaking of Lynden),

Having successfully defeated whitespot in both FW and SW with the addition of UV I am fairly convinced of how useful they are.

In the spirit of debate and going against any fabric in which we are trying to see who is right or wrong, I thought it would be interesting to get some other perspectives on the acclimation 'presentation' that you can see by clicking HERE. In short, if you scroll through the slides, they basically say that you should always drip acclimate any fish you buy from them (I might add that they are saltwater fish - it is saltwaterfish.com afterall), but that no one should acclimate corals other than to float to match water temp and then release. For the fish and other inverts, if I did the math right, I think they are suggesting an acclimation time of at least an hour and a half.

I would not be hugely against such acclimatisation for fish received in the post, but then they will have been in the box for some time and it is a little different to the acclimatisation I would do after bringing a fish home from an lfs. I certainly don't agree with the coral points. Consider how SPS corals are more susceptible to pollutants in the water than fish. Consider the extra care we put into keeping corals instead of fish only tanks. Would one really wnat to just do a quick temp acclimatisation and then throw the coral straight in? I certainyl wouldn't feel great about that.

As I said, I will never acclimatise fish for as long as inverts. The more sensitive the coral, the more acclimatisation time it gets.

 

[Tommy Gun]

How do you quickly explain to someone how to set up their tank without baffling them with terms of bio load, nitrate accumulation and maintenance regime? You tell them to stock with smaller fish at a rate of around 1" per gallon. Then once they learn more they can start to forget the rule and figure their own stocking.

You will have to trust me when I say that I have given out advice on this subject hundreds of times and my suggestion has always been to throw away the inch per gallon 'guideline' (I agree, not a rule) completely and look at each fish on an individual basis. This way, we have a much better ability to avoid spending money on an initial stocking, only to have to spend more money when we have to return some in favor of buying a more appropriate species (in my area, store credit is rarely more than 25% of the retail price).

I feel that this also doesn't take compatibility into consideration....and regardless of what anyone might say, it is not always as simply saying 'just pick all fish which are labeled as 'peaceful' on their species profile' since that is only an estimation and doesn't always imply that it will be peaceful with every fish. I suppose a compatibility chart might help out but I have yet to see one which does not have some 'iffy' advice, and of course, do not explain the advice of 'caution'.

Again, the guideline does not even cover very many species and, based upon my understanding, was a freshwater 'monster' that someone stitched into saltwater.

Besides, I am extremely strong proponent for understanding the environments which we are trying to create in an aquarium and ESPECIALLY in marine tanks, feel as though 'trial and error' or 'on the job training' regarding the building blocks of husbandry (i.e. the nitrogen cycle, stocking, water changes, and water chemistry, among others) is costly and can be argued to be unethical since we are placing life in jeopardy. Obviously aquariums are literally worlds apart from keeping most other pets such as dogs, cats, rabbits, reptiles, etc. because we have to generate a completely free-standing environment ---- hence, you would be doing a great service to explain things more in-depth. Hence, the use of the very common 'pinned' articles/topics on this forum....in fact, I don't know of an aquarium-based forum which does not use them and have written quite a few of them myself for another forum.

But I was after exactly how they are more likely to be affected. Many people claim nitrates should be less than 10ppm in a marine tank (including one of your links) yet the scientific texts say 400ppm.

My guess here is that the differences may be generated from one person/website stating what is more of an 'ideal' situation versus what one can 'get away with'.

I would also assume that none of the scientific texts say 400ppm of nitrates is ok in a reef tank?

Sadly I can't. That is just a text saying fish drink through their mouth. It says nothing about how the mere fact they are drinking the water makes them more susceptible to any problems.

The second sentence on the page states "Water gets into a fish's body through osmosis, the process in which water diffuses from a higher to a lower concentration", so it obviously doesn't state that the fish are drinking the water via their mouths. It then goes on to explain that saltwater fish have to continually 'flush' water osmotic-ally throughout their bodies in order to dilute the salt content in their cells since there is an abundance of salt available where as a freshwater fish needs to severely restrict the amount of water it 'flushes' through its body osmotic-ally because it needs to maintain the much less abundant levels of salt in its body.

My contention here is simply that this gives credence to the idea that since saltwater fish need to utilize more of the surrounding water in which they live, they are also bringing in more of the pollutants in that water as well. After all, the fish has no ability to filter them out before bringing them into their body...otherwise we wouldn't have to worry about the nitrogen cycle at all.

Written by someone in Junior High from details they found on the internet. I take issue with FW fish blowing up like a balloon as it is more likely they would just lose all their internal salts to the point that their cells and biological functions would no longer work.

Ever wonder why Gatorade can claim that it is better at re-hydrating a person than tap water alone can? One reason is because it contains higher sodium levels....and in fact, you cannot remain hydrated without having salt in your body (why many of the MRE - meals, ready to eat - soldiers eat are salty). Hence, osmotic regulation in fish is required otherwise a cell can swell from lack of water or salt.

But not how the mere fact they are in SW makes them more susceptible to any ammonia/nitrite/nitrate in the water

Let me pose the question then.....if I have shown you that saltwater fish do, in fact, use much more of the water they live in within their bodies versus freshwater, do you not think that they are also bringing in more ammonia, nitrite, and nitrate? (For the record, I realize that nitrate is not a big issue for fish at reasonable levels) In fact, can't this really imply that since saltwater fish are more saturated with the water they live in, aren't they more at risk from changes in chemistry such as pH?

Do you see my point here?

"Mollies, by contrast, can be almost dumped into seawater from a freshwater tank without problems."

Oh boy...you too!?!?!? First, he is clearly making a comparison between guppies and mollies by saying that it takes a long time to acclimate a guppy to saltwater IN COMPARISON to a molly....not directly stating that you can just throw a molly into saltwater. He also uses the word ALMOST, which hints that he is not being literal. You cannot take that one sentence out of context and use it as empirical proof that Dr. Monks is telling us to throw mollies between FW and SW tanks.

The other link to Dr. Monks comments is much more in line with what I have been trying to say....you can't simply dump mollies from freshwater to saltwater...and I haven't once said that I knew how long it would take, only pointed out that websites advice. Going on to further points by Dr. Monks, I see that he points out that some fish can be found in all three, saltwater, brackish and freshwater - but would emphasize the point that a fish in the ocean would first need to travel through brackish water in order to get to freshwater...hence, it has all that time to acclimate itself to increasingly lower salinities which is DISSIMILAR to our ability to buy a fish out of a saltwater tank, take it home, and put it directly into a freshwater tank. OR vice versa. So, please be sure to understand that I am NOT trying to argue that this isn't possible, but only that the process of doing so takes more time than I feel some on this forum may imply. I feel as though osmosis is one of the reasons why this stands true.

==============================Rebuttal to End Edits======================
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Whom do you believe, a random website, or someone with the brackish experience and knowledge of nmonks? Almost all euryhaline fishes can be moved from FW to SW in a short time

I trust them both to some degree....and again, have only argued what the definition of "short time" is with Lynden who regularly states that he and his LFS will plop mollies from FW to SW...which I am sure might work from time to time, but I am sure is risky. If he would have said an hour, then I wouldn't have brought it up, or at a maximum, asked where he got that info so I could learn more about it...even though I am not very interested in keeping mollies in my SW tanks.

I am also basing my opinion on the fact that I used to raise mollies, platies, and guppies (very old video, sorry)for use as feeder fish for my lionfish, porcupine puffer, and snowflake moray eel and have myself literally 'thrown' them into a saltwater tank and in a couple cases, had to remove them after they had died later, even though they escaped being eaten. Granted, an extreme example because they were obviously under alot of additional stress, but still....

It could. It could also be because marine water contains somewhere around 42% less dissolved oxygen than freshwater and as such there will only be enough oxygen to support half the fish.

Hmmm....wouldnt the fish have naturally evolved to deal with this already? Does this mean that there are much fewer marine fish than freshwater fish (in number, not species)?

Isn't this just another great reason for why we shouldn't overstock a tank then?

From my reference books, it would seem that freshwater fish are ingesting large amounts of water, but they do so passively across the gills (rather than actively through ingesting the water into the digestive system). This water is then turned into dilute urine which is continually produced to expel the excess water (Moyle and Cech, Fishes: An Introduction to Ichthyology, 5th edition - p 99).

I completely agree that the term 'drinking' is misleading, but you also seem to understand what I mean anyways. In fact, the term 'ingesting' is not really the right term either, but again, you know that I am not using it solely in a literal sense and neither are those websites.

Perhaps this website, which is scientific in nature (mad science network) and not solely a money making venture as one could more easily argue a .com website might be (much like fishbase.org):

[URL="http/www.madsci.org/posts/archives/dec96/847855291.Zo.r.html"]http/www.madsci.org/posts/archives/dec96...55291.Zo.r.html[/URL]

Here the same principle is described like before....marine fish take in more water from their surrounding environment than freshwater fish....but then, under the subheading of 'Marine Teleosts', it is stated:

"As a result they will tend to lose water by osmosis to the environment through their skin but mostly through their gills. Consequently, they have developed mechanisms and behavior to compensate for this water loss. Firstly, the kidneys of marine teleosts are modified in such a way that very little water is extracted from the blood, some species even lack certain kidney structures and can't eliminate water (Gordon, 1977; Moyle and Cech, 1982). This results in a reduction in the loss of water by the production of urine. However, water is still being lost by the gills and this cannot be stopped, so the only method left is to somehow replace the water as quickly as it is lost. Marine teleosts accomplish this by actually drinking water, the most reliable drinking rates reported in the literature range from 3-10 ml/(kg hr) (Gordon, 1977). However, drinking water by itself cannot solve the problem, a complex series of events must first occur in the digestive tract. These events are not yet well understood" - taken from [URL="http/www.madsci.org/posts/archives/dec96/847855291.Zo.r.html"]http/www.madsci.org/posts/archives/dec96...55291.Zo.r.html[/URL]

So, in short, does this not clearly state that Marine fishes take in surrounding water in large (relatively) amounts and then, through various methods attempt to retain that water within the body? Finally, doesn't this imply that if the surrounding water is high in ammonia, nitrites, and even nitrates (albeit to a lesser detriment), these items can also find their way into the body and may in fact, remain there for some time?

That link also touches upon ideas and info related to how freshwater fish use mechanisms to better control their internal pH (under the sub-heading of "Telosts - Freshwater Fish), but lacks the same description for the marine telosts subject....which gives motivation to learn more about this since it may help understand to what extent marine fishes can deal with pH changes.

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Special Note: I cannot emphasize enough how I am NOT trying to say that various topics are not possible - for example, I do not doubt that someone has simply dumped a molly from a freshwater tank into a saltwater tank without any visual repercussions of a visual nature, however, all of my points and opinions surround motivation(s) behind providing advice for techniques, processes, or husbandry of an aquarium. For example, while it may be possible to dump a molly from FW to SW without any acclimation, it is my opinion that a safer, more reliable technique to suggest would be to acclimate the fish for some time (I would say an hour now that I have read nmonks' post). OR, I feel as though, even if there is strong evidence that bull sharks do not need any acclimation, suggesting that one should take the time to do so may increase the 'odds' of that shark surviving....which, IMHO, is good advice for any fish one might bring home - even freshwater fish - for various reasons to include osmosis. In the end, I am basically trying to point out that what 'could' happen isn't always what 'should' happen within this hobby if for no other reason that the monetary risks involved and/or ethical repercussions for those who genuinely do not want to place his/her livestock in any more danger than is absolutely necessary. Please understand that we are simply taking a very 'scenic route' on the road to me trying to support those initial points and as has already occured a couple times, it is easy to forget those points and thus misunderstand the 'direction' I am coming from with my comments.

 

[Tommy Gun]

Because I have often seen on UK marine forums that half an hour is more than enough for fish (not inverts) and as such seeing "experts" performing zero acclimatisation would agree with that advice.

I can agree with that and have done the same myself.....again, I think the original argument surrounded the definition of "acclimate quickly" since it seemed to be suggested that one should just 'float and dump' fish which only serves to acclimate the fish to water temp and nothing more such as pH, salinity, DOC, or other variances that can occur between two tanks.

Much of my point also deals with the unknown and/or unseen. For example, it wasn't until recently that I learned that the LFS at which I buy most of my livestock (for monetary and availability reasons mainly) maintains their tanks at a minimal salinity as a prophylactic against marine ich - which is not to argue the effectiveness of doing that, but rather to point out that we may not know exactly what variances are at play and hence to what extent those possible differences will impact newly purchased livestock.

Swimming from one temperature of water across the thermocline to another where the difference is so great that shimmering occurs would not be all that slowly, surely.

Good point. But does this cover the majority of cases such as a cichlid who travels from an inland freshwater body of water which ultimately must become brackish as it increasingly comes in contact with saltwater before it gives way to complete marine conditions eventually? I mean, it's not like the cichlid nmonks tells us can be found in marine waters jumped out of the lake and was carried by wind before getting dumped directly into saltwater - or are there areas in the world where there is some sort of 'wall' which allows for complete saltwater on one side with complete freshwater on the other that a fish can cross? (not trying to be facetious with those points, and apologize if it seems like it).

Having successfully defeated white spot in both FW and SW with the addition of UV I am fairly convinced of how useful they are.

I am on board with you on this and have had similar experiences...it was someone else who said otherwise and I was trying to argue otherwise (pengy666 I believe, but was accused by Lynden of propagating 'beginner's myths' with my comments - although I think that was based upon a misunderstanding in the right, right Lynden?)

I would not be hugely against such acclimatisation for fish received in the post, but then they will have been in the box for some time and it is a little different to the acclimatisation I would do after bringing a fish home from an LFS. I certainly don't agree with the coral points. Consider how SPS corals are more susceptible to pollutants in the water than fish. Consider the extra care we put into keeping corals instead of fish only tanks. Would one really want to just do a quick temp acclimatisation and then throw the coral straight in? I certainly wouldn't feel great about that.

As I said, I will never acclimatise fish for as long as inverts. The more sensitive the coral, the more acclimatisation time it gets.

I agree completely and only bring it up because it was a topic used by myself to act as a bit more of a 'discussion board' on another forum, but became very boring because 99% of the responses stated the exact same thing as you say here.

However, I take that a bit further by taking more time to acclimate more sensitive fish...which in reality, are probably just the more expensive fish I have bought and hence, don't want to take too many risks with for obvious reasons.

I think shall place a topic on this in the science section (please understand it is not something against you personally) as it could prove an interesting point (and that area has laid somewhat dormant in terms of decent discussions lately). I would be interested to see more into this and whether it is somewhat of a myth that SW fish are more susceptible to water conditions because of their osmoregulation functions.

Obviously I am more than willing to get into this sort of conversation and wouldn't take any offense to you starting the same in the science section...might prove very useful, in fact, and I am also more than willing to change my opinion on items when it is warranted. As you can probably tell, much of my research has been done on the internet, which is risky, I know, but also lends to the problem that I often cannot remember where exactly I read the material - hence, it might be great to start a thread dedicated to this subject so that links and such can be posted, and thusly debated upon for accuracy, so that it can be referred to again. I am also very excited to 'pick' nmonks brain a little bit more on the subject of osmosis since it seems as though everyone here puts great faith in his comments - which isn't to say I don't, but I also believe that his experience may not lie directly in biology of fish even though he has obviously kept them for years and am not sure if his education is completely centered on these issues (I think he is a paleontologist, right? Just like Lynden aspires to be?!?!?) but that is ONLY because I have simply heard of him and haven't read much about the 'man behind the TFH articles' I love so much. In any case, I am certainly not 'knocking' him by any means and I still feel that in the end, he might agree with much of what I have to say.

 

[sophos9]

I am on board with you on this and have had similar experiences...it was someone else who said otherwise and I was trying to argue otherwise (pengy666 I believe, but was accused by Lynden of propagating 'beginner's myths' with my comments - although I think that was based upon a misunderstanding in the right, right Lynden?

Thats not, as I recall a fair representation of the referenced conversation - please read here for the actual

 

[Tommy Gun]

I am on board with you on this and have had similar experiences...it was someone else who said otherwise and I was trying to argue otherwise (pengy666 I believe, but was accused by Lynden of propagating 'beginner's myths' with my comments - although I think that was based upon a misunderstanding in the right, right Lynden?

Thats not, as I recall a fair representation of the referenced conversation - please read here for the actual

No offense Sophos9, however I don't know where I misrepresented anything. Did Pengy666 not say...

Im not far off a few grand and I dont really have one and to be fair I dont think I will buy one? My QT is a TL-450 which has one? and I would imagine there is more important equipment I would buy long before a UV steriliser?

Not forgetting they kill as much good as they do bad? I really cant see it benefiting against white spot all that much either? yet it may kill it in the water avoiding re infection? Im not sure there tho? But I found Mine had little effect that was noticeable in my nano? Only thing I could say I noticed was there was less critters at night with it?

...within post #9 of that thread you provide the link to and then added the additional thoughs of...

Its called taking the piss,

And if you look back at my previous posts I have had debates with a lot of other members and it came to light that a lot of people also agreed for what good they do they do as much harm, and yes I have had one in my nano?? and I had whitespot a few times.

So imho I feel they are a waste of money? for ME!

...within post #22 of the same thread, which I can and do respect and explained that at the bottom of post #28 where I said...

Again, I have also been faced with Ich even though I have a UV sterilizer on my tank...it is not a treatment or absolute prophylactic against Ich, only an added measure that can be benificial in other ways too. Don't get me wrong, I do value your opinion and am not disagreeing with you, but as with many topics in this hobby, it is easy to find conflicting opinions, ideas, and information so I am 100% sure that you have found many people who agree with you...but I could probably find an equal number of those who disagree as well. Make sense?

In short, I am just trying to provide the 'other side of the story' to help highlight what might be an opinion dressed up to look like a fact (which I am sure we are all guilty of from time to time and I am not picking on you in the least)

...while I was trying to help you express your very good point about matching pH, water temp, and other parameters during a freshwater bath, which I also was trying to explain wasn't the best Ich treatment and that to say UV is a waste of money without exploring the other benifits it can provide is not really fair...which I had already explained that UV isn't a treatment, nor cure, only one aid in prevention....but then hen Lynden tries to tear apart everything I said, ending with....

I find that statement rediculous as it's usually me or Andy that's trying to smash beginner misconceptions and it's you that always comes to reinforce them...

...in post #29. So, I don't really agree with my entirely too brief synopsis of that conversation. I am glad you point that out though because that thread was where a lot of this began; including a good example of why I was under the impression that Andywg was considered somewhat of a local expert on certain topics (which explains some of my previous comments to him).

In any case, this thread was started with the keen intention on proving that I am not trying to propagate any beginner's myths by delving deeper into the subject and the comment you quoted in just before this post was only my trying to say that I agree with Andy on the use of UV and that any comments I made that might have sounded like I was aiming at him, were actually 'aimed' or brought on by others. Clear enough?

Again, please don't "hear" any defense in my "voice" right now - but I do feel as though it is good for me to remind some people of past conversations, and/or explain what has motivated me to say some of the things I have....less I look like a completely paranoid lunatic.

And for the record, I truly feel that if Lynden was accusing me of spreading other 'beginner's myths' within that thread, I have already proved my points sufficiently in regards to everything that was talked about....in that particular conversation anyways.

 

[andywg]

But I was after exactly how they are more likely to be affected. Many people claim nitrates should be less than 10ppm in a marine tank (including one of your links) yet the scientific texts say 400ppm.

My guess here is that the differences may be generated from one person/website stating what is more of an 'ideal' situation versus what one can 'get away with'.

I would also assume that none of the scientific texts say 400ppm of nitrates is ok in a reef tank?

They didn't, but that site does not details what sort of tanks it is dealing with. Once more advice which is perfect for reefs is presumed to be necessary for all marine tanks.

The second sentence on the page states "Water gets into a fish's body through osmosis, the process in which water diffuses from a higher to a lower concentration", so it obviously doesn't state that the fish are drinking the water via their mouths. It then goes on to explain that saltwater fish have to continually 'flush' water osmotic-ally throughout their bodies in order to dilute the salt content in their cells since there is an abundance of salt available where as a freshwater fish needs to severely restrict the amount of water it 'flushes' through its body osmotic-ally because it needs to maintain the much less abundant levels of salt in its body.

My contention here is simply that this gives credence to the idea that since saltwater fish need to utilize more of the surrounding water in which they live, they are also bringing in more of the pollutants in that water as well. After all, the fish has no ability to filter them out before bringing them into their body...otherwise we wouldn't have to worry about the nitrogen cycle at all.

But freshwater fish are also taking on large amounts of water. The freshwater fish have the water flow into their body constantly at the gills and it is filtered out of the body by the kidney creating weak urine. Both FW and SW fish are constantly having water flow in and out of their body, and in fact the FW fish are trying to remove the water and retain the salts dissolved therein, so one could theorise that the FW fish are retaining more of the pollutants.

I went into more detail on this in the science thread with the explanations of the osmoregulation from reference books.

Let me pose the question then.....if I have shown you that saltwater fish do, in fact, use much more of the water they live in within their bodies versus freshwater, do you not think that they are also bringing in more ammonia, nitrite, and nitrate? (For the record, I realize that nitrate is not a big issue for fish at reasonable levels) In fact, can't this really imply that since saltwater fish are more saturated with the water they live in, aren't they more at risk from changes in chemistry such as pH?

Do you see my point here?

No. See the above. FW fish have the water coming into their body as well, so the pollutants are likely to be flowed around their bodies too. I have seen nothing in scientific literature saying that SW fish flush their body with water, only that they actively transport the salts out of the body while drinking the water in to maintain internal inorganic salt balance. FW fish are constantly having the water flowing in and out of their body, so they will probably be just as susceptible as SW fish. I still have seen no evidence, just supposition on your part that SW fish utilise more water than FW fish and therefore are more affected by it. I have seen no actual posting from any science based website or reference that SW fish are any more susceptible to pollutants in the water than FW.

It could. It could also be because marine water contains somewhere around 42% less dissolved oxygen than freshwater and as such there will only be enough oxygen to support half the fish.

Hmmm....wouldnt the fish have naturally evolved to deal with this already? Does this mean that there are much fewer marine fish than freshwater fish (in number, not species)?

There are indeed far fewer marine fish per volume of salt water than there are freshwater fish per volume of freshwater. Consider the amount of freshwater fish in rivers, and then consider the open oceans which are basically "wet deserts". Freshwater accounts for around 3% of water on the planet, and over half of this is held up in glaciers and ice at the poles. I am willing to bet that there are not 99 times more marine fish than there are freshwater fish in the world

Isn't this just another great reason for why we shouldn't overstock a tank then?

No, it's something to remember when stocking tanks and an explanation of why we have less SW fish in a tank the same size as a FW one.

From my reference books, it would seem that freshwater fish are ingesting large amounts of water, but they do so passively across the gills (rather than actively through ingesting the water into the digestive system). This water is then turned into dilute urine which is continually produced to expel the excess water (Moyle and Cech, Fishes: An Introduction to Ichthyology, 5th edition - p 99).

I completely agree that the term 'drinking' is misleading, but you also seem to understand what I mean anyways. In fact, the term 'ingesting' is not really the right term either, but again, you know that I am not using it solely in a literal sense and neither are those websites.

Perhaps this website, which is scientific in nature (mad science network) and not solely a money making venture as one could more easily argue a .com website might be (much like fishbase.org):

<a href="http/www.madsci.org/posts/archives/dec96/847855291.Zo.r.html" target="_blank">http/www.madsci.org/posts/archives/dec96...55291.Zo.r.html</a>

Here the same principle is described like before....marine fish take in more water from their surrounding environment than freshwater fish....but then, under the subheading of 'Marine Teleosts', it is stated:

"As a result they will tend to lose water by osmosis to the environment through their skin but mostly through their gills. Consequently, they have developed mechanisms and behavior to compensate for this water loss. Firstly, the kidneys of marine teleosts are modified in such a way that very little water is extracted from the blood, some species even lack certain kidney structures and can't eliminate water (Gordon, 1977; Moyle and Cech, 1982). This results in a reduction in the loss of water by the production of urine. However, water is still being lost by the gills and this cannot be stopped, so the only method left is to somehow replace the water as quickly as it is lost. Marine teleosts accomplish this by actually drinking water, the most reliable drinking rates reported in the literature range from 3-10 ml/(kg hr) (Gordon, 1977). However, drinking water by itself cannot solve the problem, a complex series of events must first occur in the digestive tract. These events are not yet well understood" - taken from <a href="http/www.madsci.org/posts/archives/dec96/847855291.Zo.r.html" target="_blank">http/www.madsci.org/posts/archives/dec96...55291.Zo.r.html</a>

So, in short, does this not clearly state that Marine fishes take in surrounding water in large (relatively) amounts and then, through various methods attempt to retain that water within the body? Finally, doesn't this imply that if the surrounding water is high in ammonia, nitrites, and even nitrates (albeit to a lesser detriment), these items can also find their way into the body and may in fact, remain there for some time?

It does clearly state so, but FW fish also do so, that is the point you are not addressing when claiming that the SW fish will have a worse affect from the water. The water around the the fish is constantly flushing into the FW fish and it will be retained, and while they pass much of it out as urine, it is passed out at the same rate it comes in, so the fish will very quickly have the same amounts in its body as the environment it is in.

It is for this reason that I feel that both types of fish will be equally affected by any ammonia/nitrite/nitrate in the water.

 

[Ehudd]

this is the exact reason i started marial arts all those years ago.
Some people just cant be wrong and all they need is a swift kick in the head.
you guys have pritty much wasted time in your life, get off the computer go out play a sport, god dam just do something else and let this slide.

Tommy i understand completely with what your saying, unfortunatley some others think their knowledge is far beyond anyone elses and they must be heard.

 

[Tommy Gun]

They didn't, but that site does not details what sort of tanks it is dealing with. Once more advice which is perfect for reefs is presumed to be necessary for all marine tanks.

There is no doubt in my mind that any one of us could relax our standards within a FOWLR or fish-only tank tank...in fact, have read/heard in a few places that you would probably have to put some effort into generating enough nitrates in order to kill a fish. However, lets not forget the fact that in many cases, we also benifit from some types of hitchhikers, hence, IMHO it still makes a lot of sense to 'preach' similar standards for any sort of aquarium...especially in the case of FOWLR tanks.

This is all not to mention that, whether directly or indirectly, by the time nitrates reach 400 ppm, I wouldn't be surprised to hear that the tank is supporting much more algae, diatom, cyano, and other less-that-desireable aquarium fare than fish...well, unless you kept them in the dark 24/7, in which case, I don't see much point in why the fish is being kept captive anyways.

But freshwater fish are also taking on large amounts of water. The freshwater fish have the water flow into their body constantly at the gills and it is filtered out of the body by the kidney creating weak urine. Both FW and SW fish are constantly having water flow in and out of their body, and in fact the FW fish are trying to remove the water and retain the salts dissolved therein, so one could theorise that the FW fish are retaining more of the pollutants.

The point isn't completely how much water is literally drank exactly, but more more so focused on how water is dealt with on a cellular level. Based upon what I have read within one of those resources, it is my understanding that freshwater fish bring water in through their mouth in order to move it across their gills, but otherwise, the vast majority of that water is expelled and doesn't hit the stomach.

You bring up the essential key here though....freshwater fish use kidneys to expell excess water from their bodies where as many marine fish have little to no kidney function at all which means they cannot expell undesireable chemicals and such like a freshwater fish can but instead rely on their gills and other functions to expell any water that it must. So, the key here being the kidneys, or lack thereof.

Tommy i understand completely with what your saying, unfortunatley some others think their knowledge is far beyond anyone elses and they must be heard.

We will see what happens in this scientific thread...the good thing is that it sounds as though no one doubts that saltwater fish are more sensitive, or that there is at least some need to stock more lightly in an marine tank, I am just trying to find the answer to why that is. I think I am just about to have the answer for the lack of oxygen theory which would put saltwater and freshwater fish on the same level there.

 

[Tommy Gun]

As a bit of a side note, I am literally watching a show on the science channel right now which is speaking of the addition of two new whale sharks at the Georgia Aquarium - which is purportedly the world's largest at the time of taping - that were caught in a fish net in Taiwan....and needed to be flown 8,000 miles to get to their new home. And in fact, they did acclimate them during the flight and surprisingly enough, it sounds like they had to adjust the temperature in the large box the whale sharks were in with big bags of ice since it must have been a hot day in Georgia!

 

[andywg]

this is the exact reason i started marial arts all those years ago.
Some people just cant be wrong and all they need is a swift kick in the head.

You know, when I did martial arts it was all about control and avoiding conflict. It's good to see that if you can't put together a clinching evidence based argument you would just revert to physical violence.

you guys have pritty much wasted time in your life,

Oh have I? I think I am best place to decide if how I have lived my life is a waste or not. I consider the pursuit of knowledge to be somewhat worthwhile. You, on the other hand, seem to prefer resorting to violence if someone won't agree with you.

get off the computer go out play a sport, god dam just do something else and let this slide.

I play rugby so I am already doing that. Just because I can type long and evidence backed posts does not mean I am on the computer 24/7. If you don't like the discussion, don't read it. No one forces you to come in here and read this, and your input has hardly been constructive.

Tommy i understand completely with what your saying, unfortunatley some others think their knowledge is far beyond anyone elses and they must be heard.

My knowledge is not far beyond anyone's. I am merely stating an opposite point and providing evidence to back it up. I am enjoying reading through papers to better understand the functions of the gills, stomach and kidneys of fish in the osmoregulation process, and I dare say that Tommy Gunn is as well. It is these sorts of debates that truly get one leafing through old reference books to see what information there is that supports or contradicts one's argument.

I think this is perhaps best now discussed in the science forum where the replies will likely be somewhat more constructive than that above. As a result Tommy, I shall probably not reply again in this thread unless a point is raised more specific to the actual keeping of SW fish than the science we are discussing.

The point isn't completely how much water is literally drank exactly, but more more so focused on how water is dealt with on a cellular level. Based upon what I have read within one of those resources, it is my understanding that freshwater fish bring water in through their mouth in order to move it across their gills, but otherwise, the vast majority of that water is expelled and doesn't hit the stomach.

It doesn't hit the stomach, but is instead absorbed straight into the blood at the gills, so is going straight into the bloodstream whereas up to 20% of the water taken in by SW fish will just pass through without being absorbed in the stomach.

You bring up the essential key here though....freshwater fish use kidneys to expell excess water from their bodies where as many marine fish have little to no kidney function at all which means they cannot expell undesireable chemicals and such like a freshwater fish can but instead rely on their gills and other functions to expell any water that it must. So, the key here being the kidneys, or lack thereof.

But the pollutants go straight into the blood at the gills, Therefore the fish will uptake them instantly. Most ammonia (around 80% is the figure I have seen before, but cannot remember where) is not lost in urine in FW fishes, but across the gills so the kidneys are not such a key figure for getting rid of nitrogenous waste as they are for just dumping the water in the blood back out without letting blood cells flow out. The end result is that the nitrogenous waste enters straight into the freshwater fish.


Now, it may be that SW fish are generally less exposed to extreme changes in climate (the oceans are pretty large and generally more stable than FW fish) and in the wild nitrogenous waste is usually very low. Many fish in fw lakes ponds and rivers may have to deal with water drying up or levels dropping meaning an essential rise in stocking per unit volume of water. This is less likely to happen in marine fish, so could explain their apparent increased sensitivity to nitrogenous waste; not because of their osmoregulation, but because an ability to cope with nitrogenous compounds is simply less necessary.

As a bit of a side note, I am literally watching a show on the science channel right now which is speaking of the addition of two new whale sharks at the Georgia Aquarium - which is purportedly the world's largest at the time of taping - that were caught in a fish net in Taiwan....and needed to be flown 8,000 miles to get to their new home. And in fact, they did acclimate them during the flight and surprisingly enough, it sounds like they had to adjust the temperature in the large box the whale sharks were in with big bags of ice since it must have been a hot day in Georgia!

There would seem to be some differences in how different places do things then. I must admit that bull sharks are noted for their ability to adapt to different environs so if any fish is going to have a lesser need for acclimatisation it would be them. I merely posted before as it sparked my interest.

Why can't the professionals agree on a standard way to do things, it would make arguments on amateur forua so much simpler

 

[Tommy Gun]

As a result Tommy, I shall probably not reply again in this thread unless a point is raised more specific to the actual keeping of SW fish than the science we are discussing.

Hang on! I just ran into some good info on that short discussion on mollies and nmonks comments on fish moving from fresh to saltwater and back!!!

While looking around for answers to better understand the reduced oxygen levels in saltwater - which you had brought up at one point - I stumbled upon this explaination about how Anadromous Fish (fish which move from freshwater to saltwater throughout its lifecycle), such as salmon, adjust from the obviously different environments. Remember I had brought up the notion that as the fish traveled between the two extremes (saltwater to freshwater), they were allowed time to adjust as the water became progressively more brackish, and vice versa? Well, this is a better description of what I was trying to say:

http/www.fs.fed.us/r6/fishing/forests/en...scorn_fish.html

you guys have pritty much wasted time in your life, get off the computer go out play a sport, god dam just do something else and let this slide.

Obviously I didn't read your post too well Ehudd - mainly because I didn't want Andy to feel as though I was going to let your comments go to my head because, as he dared to say, I am enjoying this more productive type of debate. However, I am going to let you know that you make a poor assumption that these long posts mean I, or anyone who posts them for that matter, is spending too much time behind a computer. In fact, I would like you to know that, because I have spent the last five years in college (earning more than one degree for any of you hecklers out there) and hence, can type these posts out in a very short time due to my experience with writting papers that make these posts look like a sentance. I am sure anyone who has worked on a graduate's degree can tell you, sometimes the term 'essay' does not fully encompase the length of required coursework.

I also somewhat resent the fact that anyone would suggest that excercizing one's brain is not as important as physical excersize....however, I am not a slouch since I own a few different companies, including a landscape company where I honestly enjoy geting behind a shovel and/or carrying pallet upon pallet of paver brick. I am probably one of the very last few men in my state who still maintain a natural tan from this summer.

Anyways, none of this is meant to offend anyone and of course, as I have been trying to do in other areas and subjects on the forum, I am only trying to show how one observation does not really lead to others (e.g. long posts don't equal a fat man behind a computer any more than I feel that tidal pools mean my aquarium is a tidal pool Sorry Andy and Lynden, I couldn't help myself).

 

[andywg]

As a result Tommy, I shall probably not reply again in this thread unless a point is raised more specific to the actual keeping of SW fish than the science we are discussing.

Hang on! I just ran into some good info on that short discussion on mollies and nmonks comments on fish moving from fresh to saltwater and back!!!

I am still here for these types of things.

As I said, the actual omsosis afecting nitrogenous compounds will probably get more attention from others that can contribute constructively, and it seems silly us copy and pasting much of the stuff from that thread across.

While looking around for answers to better understand the reduced oxygen levels in saltwater - which you had brought up at one point - I stumbled upon this explaination about how Anadromous Fish (fish which move from freshwater to saltwater throughout its lifecycle), such as salmon, adjust from the obviously different environments. Remember I had brought up the notion that as the fish traveled between the two extremes (saltwater to freshwater), they were allowed time to adjust as the water became progressively more brackish, and vice versa? Well, this is a better description of what I was trying to say:

[URL="http/www.fs.fed.us/r6/fishing/forests/en...scorn_fish.html"]http/www.fs.fed.us/r6/fishing/forests/en...scorn_fish.html[/URL]

Indeed they do, but those truly euryhaline fish that spend their entire life swimming from one salinity to another will have less acclimatisation time. However, for best purposes an hour should be more than enough for any truly euryhaline fish to adapt to another salinity. Sadly the filter bacteria cannot which makes varying salinities so much harder in a tank with fish in situ.

 

[Ehudd]

You know, when I did martial arts it was all about control and avoiding conflict. It's good to see that if you can't put together a clinching evidence based argument you would just revert to physical violence.

Lol are you sure you did it? or was that a female flexablity class. Some people werent gifted with such powerful brain power like yourself.


Oh have I? I think I am best place to decide if how I have lived my life is a waste or not. I consider the pursuit of knowledge to be somewhat worthwhile. You, on the other hand, seem to prefer resorting to violence if someone won't agree with you.

Dude check out all your post... I wonder if you would be this smart in a "general life" forum.


I play rugby so I am already doing that. Just because I can type long and evidence backed posts does not mean I am on the computer 24/7. If you don't like the discussion, don't read it. No one forces you to come in here and read this, and your input has hardly been constructive.

meh

 

[Tommy Gun]

Lol are you sure you did it? or was that a female flexablity class. Some people werent gifted with such powerful brain power like yourself.

Huh? What? Who? LOL, no need for too much name calling - that is, after all, my role around here these days!

Dude check out all your post... I wonder if you would be this smart in a "general life" forum.

I would say the guy is extremely well off in the 'general life' knowledge since he has put me in my place a few times by referring to his 'real life' experiences - hence the tidal pool reference. All is good man! That's all he is trying to say.

Why can't the professionals agree on a standard way to do things, it would make arguments on amateur forua so much simpler

Great point! I will place that high on my christmas list! The thing that has always bothered me is that the internet is often touted to be the 'information super-highway', however, it is equally the 'misinformation super-highway' as well....with the problem being that it is hard to figure out which is which!!!

There would seem to be some differences in how different places do things then. I must admit that bull sharks are noted for their ability to adapt to different environs so if any fish is going to have a lesser need for acclimatisation it would be them. I merely posted before as it sparked my interest.

I agree, and understand your point with the bull shark. After thinking about it for a while, it might actually make sense that they were more apt to need acclimation becuase it doesn't appear as though the Georgia Aquarium is located on any marine body of water (unless downtown Atlanta is very salty...which it might be - haven't been there in a decade or more) where as the New Zealand version states that it is using natural water.