Body is firm, very deep, oval, and compressed. Operculum absent; gill opening reduced to a vertical slit on the side of the body; gill membrane broadly united to isthmus. Dorsal and anal fins preceded by a series of 5 to 10 blade-like spines with anterior and posterior points. Pelvic fins are absent. Caudal fin deeply forked the lower lobe longer than the upper. Colour is gray above grading to silvery white towards the belly, with small black dots all over the body. Fins are faintly yellow; vertical fins with dark edges.