All posts regarding the care and breeding of catfishes from other parts of the world (North America, Europe and Australia). If you don't know where your catfish is from, post a query in the identification category.
Have you done a water quality test (ammonia, nitrite, nitrate, pH, GH, KH)?
What size pond/tank are they in?
How big are the fish?
I don't see any description of what is actually wrong with the fish - can you describe the symptoms?
Without the above information, we'd pretty much just be guessing - and whilst an educated guess may well work most of the time, it's much easier to get closer to the "correct" answer if we have more information.
also, if I may suggest, if you are very serious about this issue and the help is needed urgently, pictures would get you much farther and faster than words. Of course, the requested water parameters are a must know.