Appearance
Atheriniformes are generally elongated and silvery in colour, although exceptions do exist. They are typically small fish, with the largest being the Argentinian silverside, with a head-body length of 50 cm (20 in), but possibly up to 82 cm (32 in). The smallest species, such as the Bangkok minnow, reach only 2 cm (0.79 in) in adult length.
Members of the order usually have two dorsal fins, the first with flexible spines, and an anal fin with one spine at the front. The lateral line is typically weak or absent. Atheriniform larvae share several characteristics; the gut is unusually short, a single row of melanophores occurs along the back, and the fin rays do not become evident until some time after hatching. They scatter their eggs widely, with most species attaching them to aquatic plants.
