Colombian Shark catfish woes

[Sean OB]

We have one Ariopsis seemanni in our 6 foot 200 gallon fresh water aquarium. He had a compadre but it died when quite young, but the remaining one has been with us for 5+ years. He has been healthy and mobile up until 2 weeks ago and now darts across the tank and bashes his nose quite severely. He spends most of his time hovering by the flowing water leaving the filters.The tank is a pure freshwater, we were told this was a standard fresh water catfish by the local aquarium fish importer... I now have read that it is ment to be in brackish water.

So my dilema is that he does not have any skin conditions, so is this darting a reaction to the lack of salt or something else? If I put him in our outdoor fresh water pond of 500 gallons will he just jump out?? What are my options??

Sean

[Sean OB]

could use some advice here folks... I have done a partial water change as the nitrate levels were high, 80ppm. The tank couldn't have been all that unhealthy as there is a healthy population of little scuds that appeared naturally. 200 gallon tank should be enough size for him right?

[Viktor Jarikov]

Yes, I think he will try to bail the 500 gal. You will need some sort of protection. A netting usually works well.

As for 200 gal, what the footprint? If yours is fully grown, it must be around 1.5' TL. For such a fish a usual minimum recommended is 6'x3' but because he is an active swimmer, the minimum recommended footprint is usually upped to 9'x4.5'.

Sorry, I can only tell you what I read. You are the first known example to me where this fish survived to adulthood in fresh water. Everyone else I've read about says theirs died even as ~5"-7" juvies when kept in fresh water. Actually, now I recall one more case but their fish also died still as a young adult, I think.

An adult needs full marine water, not even high end brackish, from what I read.

Does he eat?

Options? Transfer him into an appropriately sized marine tank, little by little or find him a new nice home? Please, do not release him in the wild - you risk a chance of hurting feral fish populations.

[Viktor Jarikov]

What's a scud?

The fact that he stays in front of the filter discharge can be simply because he likes to be in the current or, as a bad sign, it can mean that the tank water is not good and has some ammonia and/or nitrite. Nitrates are about the same in both the filter water and the tank water.

[Viktor Jarikov]

Here is a thread with some similarities to your situation: http://www.monsterfishkeepers.com/forum ... t=clarotes

[Scleropages]

What is the footprint of your 200 gal tank? If it is 6' x 2', and you don't have any other very active fish in the tank, it should be sufficient for your shark cat. As you may know by now, these catfish live in a marine environment when they are adults. I would highly recommend you consider making the tank brackish, if not marine, for the long term viability of the fish.

[Sean OB]

hey folks thank you for the replies.

the tank is 6' by 2'. he does seem to be eating still, though not as much as he used to. In the last week there has been less of the darting action, but he still gets spooked from time to time and damages himself. I like the idea of installing a netting to prevent him hitting the light covers. Not sure that there is much I can do to stop him flying into the sides of the tank though. But don't worry I wont be releasing him into the wild and will keep my eyes out for a more suitable home.

The ammonia and nitrite levels are nice and low, I have done a few partial water changes to keep things in check. And scud are funny lil shrimp, they appeared all on their own and seem to be feeding off the algae. And thank you for the link to the monsterfish forum.

I am going to get some suitable salt tomorrow and try adding it gradually to the tank and hope it sorts things out. There are still only 5 goldfish in there and now one albino bristlenose youngster. Think they will handle the salt too?

many thanks
sean

[Viktor Jarikov]

Hey Sean! Spookiness and darting often arise as a result of not having enough space. It makes fish nervous because it "feels" it cannot escape the danger, often in the form of people moving outside the tank. Its appetite also usually suffers. I've seen it time and time again when I come across large fish in too small tanks. So, I'd argue for transferring the fish into 500 gal and placing the netting over the top and, as mentioned, making it full marine (3% salt, or 30,000 ppm salt), or at least high-end brackish(0.5-1.5% salt).

Gold fish can adapt to low end brackish water (~0.1%). BN pleco may not, I don't know. Common plecos do adapt.

[Sean OB]

Hey Sean! Spookiness and darting often arise as a result of not having enough space. It makes fish nervous because it "feels" it cannot escape the danger, often in the form of people moving outside the tank. Its appetite also usually suffers. I've seen it time and time again when I come across large fish in too small tanks. So, I'd argue for transferring the fish into 500 gal and placing the netting over the top and, as mentioned, making it full marine (3% salt, or 30,000 ppm salt), or at least high-end brackish(0.5-1.5% salt).

Gold fish can adapt to low end brackish water (~0.1%). BN pleco may not, I don't know. Common plecos do adapt.

Thanks a million for the swift reply Viktor. I have recalculated the 6foot aquarium's volume: 74" long x 20" tall x 18" wide, so 115.32 U.S. gallons = 436.55 liters. This tank has the goldfish and albino pleco. Definitely sounds too small for the cat now. The outdoor pond which is 500+ us gallons ( its about 3 foot deep in the middle) has a naturally sustaining population of swordtails who have been breeding for years, 7 recently introduced Corydoras aeneus and a male and female bristlenose, as well as a massive amount of plant life. I doubt I would even find enough salt to convert this pond and keep it suitably brackish for Mr.shark catfish (we get a lot of rain in my valley, wont stay very salty for very long!).... so will try adding some salt to the aquarium and keep up the hunt for finding a better home for him if he doesn't improve.

[Viktor Jarikov]

Sounds reasonable. I cannot find it: have you ever told us how long the fish is? A photo would be nice too.

Don't know your financial capabilities, but there are easy options, e.g., a 300 gal Rubbermade tub (used here to contain drinking water for cattle, horses, etc.) runs about $250. One can make a pond out of some blocks and tarp, say 500 gal for $100, or rubber liner, ~$200. Of course, one needs a pump, a biofilter etc. I am not trying to exert any pressure on you, just trying to provide food for thought.

[Sean OB]

Sounds reasonable. I cannot find it: have you ever told us how long the fish is? A photo would be nice too.

Don't know your financial capabilities, but there are easy options, e.g., a 300 gal Rubbermade tub (used here to contain drinking water for cattle, horses, etc.) runs about $250. One can make a pond out of some blocks and tarp, say 500 gal for $100, or rubber liner, ~$200. Of course, one needs a pump, a biofilter etc. I am trying to exert any pressure on you, just trying to provide food for thought.

This fella is a healthy 12-13 inches. Got some pictures below. He has started eating better, but leaves shrimp behind so changing his diet a bit to suit. I have finally managed to get a bag of marine aquarium salt, but I'm not too sure what portions to use. I would like to start at low end brackish. Got any good references I could check out??

The idea of a make shift pond would be ideal, but a lack of space and some comunal grounds politics would prevent us from doing it im afraid.

[Viktor Jarikov]

S: This fella is a healthy 12-13 inches.
VJ: So, he is rather far from the max size, which makes your current tank more suitable... still not wide enough but at least long enough.

S: I have finally managed to get a bag of marine aquarium salt, but I'm not too sure what portions to use.
VJ: ? Do you mean in what portions to divide the full dose (your current goal of low end brackish) so that the transition is gradual? I'd think in your situation maybe 10 portions, adding one portion each day (or every second day), which means on the 10th (or 20th) day you'd have your low-end brackish water. The idea is to minimize stunning/stressing the fish and the bio-filter bacteria.

S: I would like to start at low end brackish.
VJ: Low end brackish is ~1000-2000 ppm. High-end brackish is ~10,000-20,000 ppm. Full marine is about 30,000 ppm = 3% = 3g of salt per 97 g of water. So 1000 ppm = 0.1% = 0.1 g of salt per 99.9 g of water = 3.8 g per US gallon (3.785 liters). 1 teaspoon non-heaping is roughly 5 g.

It does not have to be exact, just roughly right.

S: Got any good references I could check out??
VJ: Not off the top of my head. I am sure Wikipedia, i-net, etc. must have nice articles on what brackish means.