How about a calico varigated shark. They can be a little nippy but max out under 12 inches and look pretty cool. Google varigated calico shark and see them.
The "Black shark" is a good one. However, grow absolutely huge, Up to 3 foot but 1.5-2 more likely. Very very aggressive. Hm did I say it's a good one> hahaha. Awesome fish though!
i love all the frshwater sharks but in my count i like the bala shark id shark red tailed shark rainbow shark and paroon shark..but hey i prefer balas most cause there awesome fish cause they have these multi color to them when they move but if you put them in a small tank make sure its temporary cause theyll need a 55 gal in my case cause they dont get so big but decent size btw..good luck man