Depends on the Catfish. I've seen a few pics of RTCs taking down CKs that are about the same size due to the large mouth of the Cat vs the thinness of the CK. Other than that, the CK should mix well with that stock. As for feeding...best to get them off live as soon as possible. With that collection, if the CK doesn't take pellets right away, don't worry. As time goes, it'll start taking pellets. And that will go with all the stock in there. I find Bichirs and Cats take to pellets pretty easily. And once the other fish notice one fish eating pellets, they'll realize they can eat pellets too.
