some plecos are agressive though and not only to other plecos but to other fish. Some will atack discus and angel fish my plecos from before use to atack my oscars and they would even go on a high speed chase to catch a goldfish I would often find them latter on eating the goldfish they were chasing. So it depends on the pleco and it was a common pleco not a carn but a veggie eater so never underestimate the power of the PLECO.