Portunid crabs are characterised by the flattening of the fifth pair of legs into broad paddles, which are used for swimming. This ability, together with their strong, sharp claws, allows many species to be fast and aggressive predators.
Achelous depressifrons carapace flattend in front. Colour light to dark gray. Claw arms with light blue inner surface. Legs blue. Shallow sand inside bays. Juvenile can be found on floats of Sargassum brownalgae.