At night is always the answer for feeding catfish. As they get older they may get bolder and feed during the day more too
Another option is to target feed, use a piece of PVC pipe and drop the food down the pipe with it exiting directly into the cats caves.
Two of them lay together most of the time, they are more roundbellied too.
The other three ones are kind of on their own, so these might be males, I guess.