Salt Tolerant Plecs

[LauraFrog]

I'm planning a fairly large paludarium tank. The tank I use will probably be about 80 gallons if I get my way, but it will only be about 1/3 to half full. I'd like to go slightly brackish with it, probably 1-2 tsp of salt per gallon. Are there any plecs that will comfortably live full time with this much salt? Anything very large is out because there probably won't be a bigger tank anywhere in the forseeable future, and anything very rare or expensive is out because I don't have the room to breed it - I'm currently breeding livebearers and bettas and planning on breeding kribensis and I just don't have the space to have growout tanks for more fry. I'd particularly like bristlenose because I have tracked down somebody selling albinos and marbles as small juveniles for extremely small amounts of money. I don't think she has worked out that they are valuable, but I can seriously swap a few bags of livebearer fry - and it's not exactly difficult to get livebearer fry! - for a bag full of rare BN fry.

I can also get clown plecs (might be too expensive), L333 (ditto) gibbies and common plecs (too big) and various other bristlenose that are different species (orange spot and peppermint.) I could possibly get the clown plec cheapish because the guy who breeds them is after plants on wood which I'm currently flogging and making a fortune on. I could swap him a month's work, which would retail for over $300, for a clown plec. I don't know why nobody has apparently worked out how much money you can make by propagating anubias (and bolbitus and vari lime rush and java fern etc), tying them onto bits of wood and rock and waiting.

Anyway, thanks

 

[~T~]

No, pl*cos are not in any way salt tolerant.

 

[nmonks]

Actually, quite a few plecs naturally inhabit slightly brackish water. Several species do so in South America, though these are as good as never traded, for example Hypostomus watwata and Hypostomus ventromaculatus.

Additional species have been found to inhabit brackish water outside of their natural range, particularly in Florida where multiple species have established themselves in fresh and brackish water canals, most notably Hypostomus plecostomus which has been described as having a "broad salinity and temperature tolerance" by the Gulf States Marine Fisheries Commission. It should do well at up SG 1.003, possibly slightly higher.

That said, I actually recommend skipping plecs if all you want is algae control; nerites will do a much better job and are far more characteristic of brackish water habitats. If you want a catfish, a prime choice is the brown hoplo Hoplosternum littorale, a hardy species that prefers slightly brackish water to soft water conditions, despite being a Corydoras relative. It would be a good choice for a tank up to SG 1.005.

The idea "catfish are allergic to salt" is a nonsense, with many families including species that occur in brackish water. There are Synodontis, pimelodids, bagrids and silurids for example that all inhabit brackish water in some part of their range. At least five families have species that can live in the sea: the ariids, the banjo catfishes, the bagrids, the pangasiids, and plotosids.

Cheers, Neale

 

[LauraFrog]

Thanks for the info! I think some of those, like the common plec might be out because they get too large but I'll have to look into all of them. My LFS is a big believer in salt, they use about 1-2 tsp/gallon in all their tanks all the time because it reduces their disease rate or so they think. They've never had a problem with that salt level on cory cats, bristlenose or loaches, even the ones in their display tanks that are always kept with that much salt. They have this big display tank, overstocked, about 2tsp/gallon of salt in it, containing cardinals, neons, two bristlenose, a heap of albino aenus corys, a large number of Australian and NG rainbows, congo tetras, big gouramis of various species, etc etc. They also add a large amount of salt - about 5tsp/g - to their plant tanks, which are stocked with platys and rosy barbs. So I guess most of the plants I'd add to it are salt tolerant.

If I do put salt in there it's not going to be much, not sure how much, but just enough to keep mollies that have been raised in freshwater healthy. I have tried, time and time again, to keep mollies healthy in freshwater but no matter how clean the water is, I'm besieged by columnaris, ich, velvet and finrot that never seems to infect anything else. I can get Australian native shrimp that are good algae controllers and will tolerate quite a lot of salt, so I'm not really worried about algae, I just like the look of bottom dwellers. Like I said I don't even own the tank yet, so I have loads of time to research and work out what I want.
I'd kill for synos but they might be a bit out of my price range. I don't mind forking out for the tank, because it will always be mine if I look after it. But I'm going to university in a few years and my parents - who DON'T get fish - have utterly refused to look after my fish in my absence. Which means that the vast majority of them will have to be rehomed, so I'm trying to choose common-ish species that are easy to look after.

Thanks for the help, I'll go and look up the species you mentioned.

BTW, there's some Australian species, an eel tailed catfish. It's hard to get because it's only just gone up on wholesaler's lists and everybody wants one, so I'm hoping the price comes down. It's salt tolerant as far as I know.

 

[nmonks]

All the Australian native catfish are ariids or plotosids, and even those that live exclusively in freshwater now evolved from marine ancestors, and I'd predict they're salt-tolerant in most cases, at least up to a point. The eel-tailed catfish is some species of plotosid, likely Tandanus tandanus. These are fairly big fish, and predatory, though not especially aggressive or difficult to keep.

I'm not a big fan of randomly adding salt to freshwater tanks. It's very old school, and any beneficial effect it has is marginal, and quite possibly outweighed in the long term. It's always important to remember aquarium shops don't hold their fish for long: conditions that are acceptable for a couple of months may not be acceptable for the home aquarium where you want to keep and breed fish across many years. Many freshwater fish are known to react badly to salt in the long term, in particular Rift Valley cichlids.

In the past people used salt because it kept fish healthier under the conditions aquarists used to create. Until about the late 1980s, aquarists maintained "old water" was better, and avoided doing water changes. I have books that recommend water changes of 10-20% per month! Nitrate levels were often extremely high as a result, upwards of 100 mg/l. Filter systems were often poor, and even large tanks would rely on often-underpowered and badly maintained undergravel filters. So you'd have high levels of ammonia and nitrite too.

Sodium chloride detoxifies nitrate and nitrite, making it easier for fish to stay healthy in poor conditions. Hence aquarists who added small (teaspoon per gallon) amounts of salt would observe improvements in their success.

In our more enlightened age we routinely do big water changes and employ far more efficient filters, or at least we should be! No aquarium writer today recommends adding salt to freshwater tanks, so you won't see it mentioned in books or magazines. Advanced aquarists don't use salt this way either. It's very much something done by old-fashioned aquarists who haven't changed their habits, and newcomers to the hobby who got sold the salt by their retailer. Instead the focus among experienced aquarists is on preventing problems with water quality rather than coming up with ways to minimise their effects.

In parenthesis, it's worth mentioning that one or two teaspoons per gallon of water will not be creating brackish water conditions. While you may observe a therapeutic effect of some sort as far as mollies are concerned, you absolutely will not be creating an environment where brackish water fish would be happy. So for all practical purposes your tank is a freshwater one, and you can add whatever freshwater fish you want.

Cheers, Neale

 

[LauraFrog]

Okay, thanks. I don't really want to go fully brackish, because it's hard to stock (all the fish cost a fortune because it's considered specialist) hard to rehome the fish (as soon as people hear they can't randomly throw them into their tank they aren't interested) and hard to plant. The mollies I want to keep are hybrids, pretty standard pet shop mollies but they are the larger sailfin strains and I haven't had success keeping them in pure freshwater. Since they are raised in freshwater I thought that a small amount of salt would make a fair difference. Am I wrong?
Also, the water I am using is very soft, my tests are reading it about 3 degrees kH and about 5 degrees gH. So that might be the problem with mollies. I'm tempted to put coral sand or limestone in the filter and try again but I dont' think it's fair gambling with fish's lives, and I don't want to stuff around with the water chemistry anyway because the tank is fully stocked and established.
The eel tailed catfish is Neosilurus. I have seen them in brackish tanks with archerfish and some of the large brackish gobies and gudgeons in an Australian biotype tank. I'm not sure whether they require salt or just tolerate it.

 

[nmonks]

I don't really want to go fully brackish, because it's hard to stock ... hard to rehome the fish ... and hard to plant.

I'd argue with all of these comments, but I'm biased!

Since they are raised in freshwater I thought that a small amount of salt would make a fair difference. Am I wrong?

Nope; small amounts of salt can make a difference, particularly in soft water conditions.

Also, the water I am using is very soft, my tests are reading it about 3 degrees kH and about 5 degrees gH. So that might be the problem with mollies.

Absolutely! This water is great for South American and Asian freshwater fish, but not for Central American species. Adjusting water chemistry is possible but I NEVER recommend people do this unless they fully understand why and how. The risks of causing stress on the fish by allowing fluctuations in water chemistry if you don't know what you're doing are very great.

The eel tailed catfish is Neosilurus. I have seen them in brackish tanks with archerfish and some of the large brackish gobies and gudgeons in an Australian biotype tank. I'm not sure whether they require salt or just tolerate it.

Most Neosilurus are freshwater fish in the wild, though some, e.g., Neosilurus gloveri, are known to have a high tolerance of salt. Do refer to Fishbase for more.

Cheers, Neale

 

[LauraFrog]

Okay, thanks for the advice. I might go freshwater with just enough salt added for mollies then. Most of the species I'm interested in will tolerate moderately hard water, and this tank is something that's happening 'when we move'. (If I had space now be assured I'd already be cycling that sucker! I sorta know which tank I want and my father has said he'll get it, because he was thinking I'd want a swimming pool circa $30k, but I said I'd prefer a large fish tank circa $1-2k. Reasoning that when I get set up on my own I take the fish tank with me, but the swimming pool stays with that house as a liability for my parents to try and look after when they get old.)

We're starting work on 'the block' at the moment, and it's looking good. We are going to have town water - which is the same water I'm using now only treated, I haven't actually bothered to test it. Bore water, which is a fair bet will be reasonably hard, but which has a pH of somewhere around 7.4 so it's not too bad in that regard. AND rainwater. So I think I'll do a bit of a fish shuffle and have a softwater tank and a hardwater tank with a bit of salt added. I'm not going to try and adjust the water chemistry in the tank I have at the moment. The only 'hardwater' fish in there are platies, which were raised in soft water and do not seem in the least unhappy judging by their breeding rate. Everything else in there prefers water soft.

The catfish I've seen for sale is gloveri. A tankbuster apparently. I wish they would WARN PEOPLE that their fish grow to be as long as the tanks they're putting them in! AND its' a threatened species so you get idiots buying one. At least my LFS never stocks plecos, gibbies, gigantic juvenile cichlids (except oscars which they don't sell to fools) really aggressive fish, etc etc.

I would absolutely love to get a small brackish tank, probably something around 15 gallons and then stock it with bumblebee gobies and some brackish natives like smaller gudgeons, native gobies and the Pseudomugil blue eyes which can be kept in freshwater or marine but are at their best somewhere in the salty end of the middle. The problem is my parents who are already complaining long and hard about the fish, like the veranda being clogged up with breeding/quarantine tanks, the electricity bill (which I have offered to pay part of to no avail) and the lack of space in my cupboard due to betta tanks.