The Atlantic sabretooth anchovy measures up to 23.5cm. It has a silver stripe up to twice the eye diameter at widest, which disappears in fishes over 10cm. In colour it is greyish blue dorsally with yellowish fins and translucent membranes and a blackish caudal margin.
Atlantic sabretooth anchovy cccurs in brackish estuaries and adjacent marine areas but also reaches freshwater. It forms moderate schools. As an anadromous species, it migrates from estuaries or the sea, but possibly the limnichthys of Lake Maracaibo and the amazonensis represent purely freshwater forms. In freshwater, it feeds principally on small fishes, prawns and copepods; also insect larvae. At sea, it feeds on fishes and various crustaceans.