Injected Co2 = More Active Corys?

[iairj84]

Oh yeah, and I thought I'd just echo the point that Ben Folds made, adding CO2 to a tank doesn't mean there is any less oxygen in there .

This is true to some extent, when the CO2 is at the right levels then this is very true, but if you're injecting too much it can take too much out of the air for the fish.

 

[Bozza]

No i didnt test the water before and after. I know I should have. That could very well be what has happened. Thanks three-fingers

 

[three-fingers]

This is true to some extent, when the CO2 is at the right levels then this is very true, but if you're injecting too much it can take too much out of the air for the fish.

Kind of - adding CO2 to the water still doesn't mean there is any less oxygen in the water - but yes - adding too much C02 can stop fish breathing properly. Fish depend on there being a higher concentration of CO2 in their blood than in the water in order to get rid of C02, so when there is too much CO2 in the water they cannot respire properly.

~30ppm of CO2 is perfectly safe. I've seen fish take up to 60ppm with no problems, but it really does depend on the species.

How much CO2 concentration a fish species can take depends on what type of environment it is adapted to.

In the case of corydoras, If they weren't breathing properly through the gills due to CO2 being too, the reaction IME would be swimming upside down gasping for air just as any other fish would...
But I cant be 100% sure, as I haven't kept corydoras in years and I know little about their particular physiology.
Corydoras like oxygen rich water - however I presume their ability to swallow air is an adaptation to help them cope in a low oxygen environment (I remember reading this somewhere ages ago, apparently in some localities their river/streams dry up leaving them in small ponds).

But It's far more likely to be a lower pH increasing their 'vitality', and personally I wouldn't be surprised if they were to spawn (I've heard this happen with tetras before) .

 

[jollysue]

It is beginning to sound like there is lots of speculation. Might want to check with Bryan or one or our resident Cory experts on some of this regarding Cory adaptions.

Some Cories--such as Pandas--are reputed to have very high needs for oxygen. I have seen all fish grab air at the top, and I get suspicious every time. Even my fronts have done it without turning over on ther backs.

I would be interested in this description of Cories adapting like Anabantoids to stagnant pools. If there are Cories that do that, it might be a small number of select species.

 

[Bozza]

I didnt know this topic would be so interesting and have many people respond. The Co2 kit I have is a basic kit. Its from Nutrafin (something like that) I think its from a european company. So therefore I cant be sure how much Co2 the kit is producing. I do keep an eye on the tank and fish for any signs of lack of oxygen. I do turn the air curtain on at night after lights out and since adding the co2 kit I have added more water movement up top by moving the filter outlet. I was thinking of putting it up on one of the more catfish orientated forums.

 

[jollysue]

Well., I think that's a great idea. As amatter of fact I asked about part of the subject under discussion at our favorite importers specialty forum:

[my post]:
There are often discussions that come up about Cories gulping air at the surface.

I get anxious when any of mine do it much and always do a water change. But elsewhere there was a question about Cories that were swimming more and gulping air after a co2 injection was added.

One reply concerned someone's vague memory of reading about Cories gulping air as an adaption to river streams drying out and leaving Cories in puddles. I have my doubts about Cories living as Anabantoids without the labyrnth organ, but I thought I would put it to the experts here. How much air do Cories get from gulping air? Is it a neutral behavior which ought not to cause any alarms? Are there Cories that live in mud puddles and swallow air to live?

and got this reply:

Corydoras have the ability to utilize atmospheric oxygen by gulping air at the water surface. The oxygen is absorbed through the gut which is called gut aerial respiration. This happens in many an aquatic creature and is quite complex so rather then bore you with a physiology class it's not something to be concerned about nor are they mud puppy like let alone adapated to streams drying out and leaving them in puddles ! [my red emphisis]

Join the discussion there, Bozza. Oops! I see we have two threads going there? haha

 

[Bozza]

Yeh I thought id be cheeky and start a topic on the corysrus forum hehe. Just want to see what other things come up about this topic because it is interesting. I would like to know how the gut aerial respiration works. It sounds interesting

 

[jollysue]

Google or that other one for definitions

 

[three-fingers]

nor are they mud puppy like let alone adapated to streams drying out and leaving them in puddles !

I never said puddles . Just small ponds, 'small' is a subjective term though I should have been clearer. They are very small compared to the river. I still remember reading it...but I'm not entirely sure where, I think it was in a couple of places. Either way those sources can't exactly be counted as reliable since I don't even know what they are!

I'm thinking aloud here btw ...maybe I'll invent some different oxygen levels - very high, high, medium, low and very low.

The ponds I'm thinking of are medium-low, where as the main slow moving rivers/streams would be high. Nothing like anabantoids have adapted to live in (medium-very low), but less than the average aquarium (high-medium).

But I don't know why they would still have such an ability to take air from the surface using this cool sounding 'gut aerial respiration', If they always lived in the high oxygen rivers, why would they need it? Does it serve any other purpose, or is it just something lots fish happen to be able to do for no apparent reason?(and if thats the case, why are corys renowned for it?) Lol, as I'm typing, my synodontis has just loudly taken air from the surface .

For comparison, hillstream loaches come from very high-oxygen content rivers and don't usually last long in the average aquarium with high-medium oxygen levels, they need a river set up with powerheads and the like.

However with corydoras it would vary a little between the species, to what extent I'm not sure.

Planted aquariums on the other hand typically have very little to no surface agitation, and injected CO2. CO2 at 30ppm is no problem at all to most fish (and at least C.aeneus). The other thing to note is that the plants will be taking C02 in and putting oxygen in the water. Is it just one nutrafin canister on a 60 litre? Using your own yeast mix or the included packets? Your lucky if you can bring it over 30ppm with just one of them on a 60 litre anyway so I wouldn't worry at all .

I'm 100% that if your corys are more active and you haven't changed anything else, it is the CO2 (+ the resulting carbonic acid) lowering the pH .

Btw if anything comes up in that thread to do with corydoras living in small pond remnants of rivers, can someone maybe post it here? Apparently you need to be 17 or over for that forum and I wouldn't want to break the rules .
I'm interested in corys because I've been planning on getting some more from corysrus.co.uk for ages now, and it will only be another couple of months before I have a tank well suited to a decent sized shoal of them .

Edit: Here's the closet thing to a reference I can find at the moment - Planet Catfish. That's not where I first read it though . And those pools are bigger than I remember from the other reference. I think those ones would still contain substantially less oxygen than the river.

 

[Bozza]

Well really its more of a 50L hehe. But yes there is only one canister and I am using the included packets.

 

[jollysue]

There are unnumbered species of Corydorus through out MesoAmerica; many are still unidentified. As you mentioned loaches, lets compare there: Loach needs as you infer are varied depending on their adaptions. It is the same with Cories. There are a variety of aeneus spread thoughout the S.A. continent. In general aeneus are one of the easiest Cory species to keep. But like the loach you mentioned, there are species that are much narrower in their requirements. So certainly there are some species that require more aeration than others.

On the other hand, the Cory behavior of darting to the surface to gulp air being idiosyncratic does not mean that gut aerial respiration is limited to Cories, only that they dart to do it. I have seen many kinds of fish hang at the surface to sip air before they turn over belly up.

Any puddle or pond without water exchange will loose oxygen--salt sea/dead sea--it seems to me. The article in planet catfish seems to indicate several species of fish in the pools. Nevertheless pools are not necessarily lacking in water exchange. I saw nothing about adaption by Corydoras to live in oxygen deprived/severly depleted waters.

As the quote from Bryan says, gut aerial respiration is an adaption of many fish, but it does not equip fish to live in long term adverse conditions.

This is the article posted elsewhere regarding ph and o2 fluctuations: here

 

[Bozza]

Thanks jollysue for that article on ph and o2 fluctuations will read it in the future have it bookmark for future reference.

 

[jollysue]

Well, as you know it was posted in answer to your thread.

BTW, three-fingers, the age limit has been lifted. I asked as I could see no reason for it. There are other resrictions that would limit inappropriate juvenal behavior. Try again.

 

[three-fingers]

I saw nothing about adaption by Corydoras to live in oxygen deprived/severly depleted waters.

As the quote from Bryan says, gut aerial respiration is an adaption of many fish, but it does not equip fish to live in long term adverse conditions.

I think that corydoras in general are equipped to a certain extent to deal with low oxygen environments using gut aerial respiration, but more coincidentally rather than evolving with this adaptation. Gut-aerial respiration looks like one of the main features for fish in the family callichthyidae, some species being dependant on it and can deal with extremes thanks to it.
Since it appears all corydoras hail from high oxygen content moving waters, it sounds like they have become almost dependant on this oxygen and that gut-aerial respiration is something like the human appendix, it was important at some time when they were a different species, but no more. Given enough time, the ability will probably disappear completely in a lot of/some of them (though by the time it goes they could very well be different species anyway).

However, as mentioned the genus corydoras is very widespread throughout south America, and there are many different species, different forms of the same species and possibly subspecies. They all live in flowing water (as far as I'm aware, is there any lake corydoras?), and some of them will live in rivers/streams that dry up considerably in the dry season leaving them in ponds, reducing the amount of oxygen available for a fish that normally requires high oxygen levels (not to say there's very low oxygen, just too low for oxygen loving fish like corys). For those species, the ability to use gut-aerial respiration would come in handy so they would most likely keep the trait (unless it means they are at any disadvantage).

I have seen many kinds of fish hang at the surface to sip air before they turn over belly up.

Although that has probably got more to do with a combination of the fact that there more oxygen at the waters surface and desperation, rather than those fish having the ability to use gut-aerial respiration, since isn't that how all fish react when there's not enough oxygen in the water/they cant breath properly? .

Edit:

BTW, three-fingers, the age limit has been lifted. I asked as I could see no reason for it. There are other resrictions that would limit inappropriate juvenal behavior. Try again.

Oh thanks! Being a member of there is going to make me want corydoras even more now :.

 

[jollysue]

Yes, three fingers. Then you can check the facts that apply to your speculations.