No tank mates, except peppermint shrimp & plenty of corals. The first one I had did really well with others (Yellow Tank, Blue Tang, Damsel, Copperband)... the only problem was the cowfish is a slow eater. I had to pay attention to make sure he got enough food. This time he is the king of the tank…
They are poisonous though. They can let out very toxic poisons when stressed.