Small to medium sized marine and freshwater fishes; maximum size about 70 cm, commonly 5-10 cm. Body slender cylindrical or somewhat compressed with round belly. Mouth small and terminal; hind tip of upper jaw not extending to posterior margin of eye. Two dorsal fins well separated, the first with III to VIII flexible spines separated each other at base; the second dorsal and anal fins with a single spine followed by soft rays (D2 I, 7-13; A I, 8-21); caudal fin forked; pectoral fins high on the sides of body with 10-19 rays; pelvic fins abdominal to subabdominal with I, 5. Scales cycloid, relatively large; lateral line absent. Color: body greenish or greenish brown dorsally, silvery ventrally; a broad silvery (black in preserved specimens) stripe on the side of body.|
Similar families occurring in the area. Atherinidae is distinguished from the following similar families in having round belly, anus located behind pelvic fin base, 2 dorsal fins, first dorsal fin spines separated each other at base, and a single anal fin spine. Engraulidae: hind tip of upper jaw extending beyond posterior margin of eye; a single dorsal fin; no spines in fins. Isonidae: body compressed with keeled belly. Mugilidae: first dorsal fin with IV spines, anterior 3 spines close together at base; II or III anal fin spines. Phallostethidae: anus anterior, located under head.
Remarks. Occurring in tropical to temperate marine, estuarine, and freshwater areas; usually found in beaches and seagrass areas. Eggs with entangling filaments on chorion.