Columbian shark is sick need help to save him

[sharkfish]

I just got a new tank its about 10gallon all my fishes are doing great but my Columbian Shark is not looking too well he doesn't eat or doesnt do anything. I had two but he died what can I do to help him I have fresh water fish

 

[AbsoluteFaye]

Try posting in the freshwater fish section. You'll probably get better answers. Good luck!