they can be territorial as they get older and could harass tank mates but shouldnt be too bad when there young and i would recommend keeping only one of them per tank prob they can grow to 6+ inches up to 11inch i think is max
It has a reputation for becoming increasingly jealous of its territory as it matures, and also can be aggressive to fish, especially slow, flat-bodied fish. In the home aquarium, the algae eater makes a poor tank mate. It is very aggressive and boisterous; they often attack other fish and rip off scales, causing infection. It rarely swims to the surface as it likes to be on the bottom of the tank. It is very hardy and can survive in semi-dirty water, plus a wide range of temperatures, 60 - 90F (16° - 32°C), allowing it to be sometimes kept in unheated aquariums indoors