Shark Catfish - Cause of Death?

Question

A while back I got a pair of shark catfish - I was very taken with them, and although they are currently only in a 60 gallon tank, they'll get moved to a bigger tank as they grow.

At least, that was the plan. Then one of them died. I put that down to bad luck - I'm not exactly what you'd call experienced at this, but the other one seemed fine, so I wasn't really concerned. Then a couple of weeks ago, I got two more, making three in total, and in the last week, I've lost two of them.

1 might be bad luck, but even I know that three means there's a serious problem! Even so, the remaining catfish is looking very healthy and acting normal .

Anyway, although the fish shop told me they were freshwater, I've read that they prefer to have some salt in the water as they get older, though these fish are still pretty young, judging by their size.

So, could that be the problem? If not, what could be casuing the deaths? None of the fish showed any sign of having ben attacked...

Answer 1

You'd be wise to start adding the salt - they only live in freshwater to reproduce.

You may have had problems with ammonia and nitrite building up in your tank, especially if it's relatively new (less than 2 months old) and there are other fish. Do you test for these? Are you doing partial water changes of at least 25% each week? That would be my first suspicion. The ammonia and nitrite problems acn also occur if you've used an antibiotic in the tank recently. And the cats will be sensitive to medications, so you should only use hallf-doses to start and build up gradually (stop if they show signs of distress and do a 10% partial water chage to remove some of the medication if that happens).

Answer 2

Thanks for the answers. I've picked up some marine salt and a hydrometer from the pet store today.
I've had the tank for about 5 months now. I do test for nitrates and ammonia, though not as often as I used to when the tank was new. I've been doing a 50% water change every 2 weeks - should I be doing it more often?
midraj - I certainly won't be giving up, I'm far too taken with these fish for that ;) Kinda addictive, watching him swim up and down.

I've got a couple of other fish in there - some african rope fish and a young dragon goby. Will they be able to survive in a brackish environment, or will they need to be in a seperate tank? I read somewhere that most gobies are ok in brackish water, but wasn't too sure if that included dragons or not.

Thanks for your answers

Answer 3

Just for their overall health I would switch them(well the one you have) to a brackish water tank environment. Just to let you know Brackish water is more than just a little salt in the tank. It really is a different environment on it's own. So go on and suck it up. You've come this far. Go to the pet store and get salt meant for saltwater tanks and a hydrometer and bring that water up to about 1.0005.(remember to do this slowly for the sake of the one you already have) and try again! Sorry for your loss.