They are a pain in the ass to get feeding to start with, as they are all wild caught (or as I said before used to be, not sure now though) they tend to only want to take live food.
Wouldnt worry to much, when I got mine it took maybe 2 weeks to get them to feed, once I "broke" them in kind of thing they turn into right little gluttons, one of mine is still kind of picky, but the other one will eat literaly anything, he will gorge himself on pellets I give my Oscars, the bits that they drop etc, he swims about nabbing it all.
To me it just looks like a Lima with a slight deformaty, just happens to have been born a bit different, though someone feel free to correct me.
Nice little fish, if you get worried about it not eating try some live worms or something, but I kind of starved mine untill they decided to eat something that wasnt alive, most predatory catfish can go a long time without food, as can most fish in general.
Oh and little edit - they can hang around anywhere, mine tend to hang around some plastic reed type plant I have vertical with their nose down, its how they hunt in the wild, very rarely just sit on the bottom like other cats.