What do pleco (suckerfish) eat?

Young pleco fish generally eat algae on the tank bottom as well as the waste, plankton, and daphnia of other fish, giving them tank-cleaning ability, so they are often kept as utility fish in aquariums to reduce cleaning work.

But once a pleco grows up it starts preferring small fish, shrimp, and earthworms, and will scramble for artificial fish food too, so its tank-cleaning ability weakens. Plecos have few natural enemies in the wild and are very hardy, eating almost anything; basically any food normal fish eat can be fed to them.