Do Algae Eaters Eat Fish?
They can, but it depends on the species. Chinese algae eater are horrible fish in the fish keeping hobby. While they are young and small, they are great for eating algae but as they get older they start harrasing other fish in the tank by sucking off their slime coatings and expose them to illness and disease. Very large specimens of hypostomus plecostomus (your common pleco) can eat smaller, slow swimming fish and invertebrates like ghost shrimp or baby fish when they are newborns.
