Sargocentron diadema, known commonly as the crowned squirrelfish, is a species of marine ray-finned fish belonging to the family Holocentridae, which is the only family in the order Holocentriformes.

Squirrelfish in general are large, active, nocturnal fish which are usually red in color.

[2] The crowned squirrelfish is commonly found on the reefs of the Indo-Pacific, from East Africa to Tahiti.

[3] The fish is bright red with thin white lines crossing from the gill cover to the caudal peduncle.

It is an active, shoaling fish which is kept in large tanks with other individuals of the species.