Diseased catfish

Question
These are wild catfish between 1 & 2 inches long and growing.  I do not know the species.  Their fins have blackened and look ratty.  There are also large dark patches on their bodies.  I tried doing searches for black spots but what I found were diseases that cause little spots, specs really.  These spots cover some territory on the skin.  Can you give me an idea what this may be?

Answer
Hi Earl,
I definitely think the dark/black patches are due to ammonia burn as well as the ratty fins too. If these catfish are kept in a recently setup tank, the "biofilter" or good bacteria haven't yet been able to establish to control the ammonia and nitrite level.

I would start doing daily 75% water changes and use a water conditioner that neutralizes ammonia like PRIME or AMQUEL+ and try to get some water samples to your petstore or test the water yourself for ammonia, nitrites, and nitrates.

It takes an average aquarium about 4-6 weeks to finish cycling, sometimes sooner, sometimes later.

Best of luck and I hope this helps!
Karen~