i bought one about a month ago. they have some info on planetcatfish. i think it says they may try to eat smaller fish when adult but mine is very, very passive. it eats flake food and swims around at the top under the lip of the hang-on filter. actually i never even remember its in there til the water level drops a couple of inches and hes forced out.
I have 1 at the moment. Had 2 of them for about 2 months until he got killed by the other one. I've had him about 2 1/2 months now and he has grown dramatically. He is currently housed with 6 assorted yellow, black, and brown bullheads and 1 syno. ocellifer. They are all of equal size. He is always fighting my yellow bullhead who is king of the tank and keeps losing. Feisty fish though.