(EN) Striped Catfish - (FR) Poisson-chat rayé
Plotosus lineatus subadults in Reunion Island

Striped catfish form compact "balls" such that most predator will be deterred by the innumerable venomous pectoral spines. They do so until they are fully grown, although most of the time the ball will lose many members along the way, and in the end only a few of them remain at adult age.