Are there any endangered species of starfish?

Depends on the particular variety of starfish, but they're all important food sources. For example, the common starfish gets eaten by seabirds, dolphins, porpoises, gulls, sea otters, lobsters and crabs, and by several species of fish -- as well as other starfish! And Humans of course.

The crown-of-thorns starfish (the notorious predator of coral reefs) is itself eaten by various fish, such as the humphead wrasse; by the harlequin shrimp; and by the giant triton.