Well i guess it depends on how big your tank is.....i have a red tailed shark and they go well with a few barbs......5 or 6. The shark tends to be a loner and leave things alone when theyre in larger groups. The barbs often get a little nippy but their aggression seems to be eased when in larger groups.
Bala sharks, Betta (Siamese Fighting), Bosemani Rainbow, Cherry Barb, Clown Loach, Dwarf Neon Rainbow, Flying Fox, GloFish, Iridescent Shark, Kissing Gourami, Kribensis, Otto Catfish, Pearl Gourami, Penguin Tetra, Pleco (Common), Rosy Barb, Sparkling Gourami, Tiger Barb, Tin Foil Barb, Three Spot Gourami, Zebra Danio, are a list of some compatible fish although usually these other fish are happiest when in larger groups just like the barbs.......it really again depends on ur tank size.