Peppermint shrimp are omnivores that will feed on leftover foods, and sometimes pick at algae. Most importantly though, they will eat nuisance aiptasia anemones and are an excellent choice to treat this scourge. They do best in groups when tackling an established aiptasia problem. Colorful with interesting behavior, they will make good pets after handling the aiptasia in your tank. It takes them very little time to train most hobbyists to feed them when they approach the tank by doing a dance on the front glass the hobbyist often finds pleasing and worthy of reward. :)
Peppermint shrimp, like most shrimp, will kill snails if they are hungry, and they are especially dangerous to stressed snails, so they should be target fed on a routine basis.