Male cleaner fish will punish female cleaner fish if they try and steal food by taking a bite out of the bigger fish they clean, according to research from the University of Queensland.

Cleaner fish live in groups with the largest fish becoming the dominant male (all cleaner fish are born female). One possible reason for punishing females is to stop them from eating too much, growing large and turning into a rival male.

The punishment acts as a deterrent, with female cleaner fish adjusting their behaviour to avoid future punishment.