Alex Mustard / Shoal of Convict blennies (Pholidichthys leucotaenia) forming a tight ball, defensive behaviour, on a coral reef, Raja Ampat, West Papua, Ceram Sea, Pacific Ocean.

David Fleetham / Schooling Convict fish / Convict blennies (Pholidichthys leucotaenia) juveniles, in a tight ball formation, Philippines, Pacific Ocean.

Alex Mustard / Mixed school of diagonal-banded sweetlips (Plectorhinchus lineatus) and ribbon sweetlips (Plectorhinchus polytaenia) gather above plate corals, with convict blennies (Pholidichthys leucotaenia). Saund...

Alex Mustard / A mixed school of diagonal-banded sweetlips (Plectorhinchus lineatus) and ribbon sweetlips (Plectorhinchus polytaenia) gather above plate corals, with convict blennies (Pholidichthys leucotaenia). Sau...