Please advise!

[Marsha4524]

I had two pictus catfish and for six months they zoomed around only on the bottom of the tank and even hid a lot. Two weeks ago one stopped eating and appeared to be struggling to stay at the top of the water, gasping. Then he died.
Now my other one is swimming listlessly back and forth at the top of the tank, refusing to eat. It has no visible marks or diseases and I don't want to lose him, too. All of the other fish are healthy.
The tank is a 55 gallon community tank with a biowheel filter and a canister filter. I replace 1/3 of the water monthly.
What can I do?

 

[Lisachromis]

Upping your water changes might help out. I find that you're doing what I'll call the bare minimum for a lightly stocked tank. I would try doing an extra water change now, and see if that helps get the appetite back. You might want to make your water changes at least bi-weekly.

Another thing to try is to feed your pictus at night. Maybe try some pellets. If that doesn't work, you might have to try some live food of some sort.