Keeping other types of fish are a bit dicey when you keep sharks. Some are very bad tank mates - such as triggers, large angels, & puffers. Also any fish that is small enough for the shark to eat is a poor choice - as the shark will eventually prey on that fish.
The groups of fishes which have the best change of compatibility - includes Eels, Groupers, Sweetlips/Grunts, & Foxfaces, in addition to other sharks and rays. But it also depends on the species in question.