Megalamphodus sweglesi has a maximum
standard length of . This species has no less than three colour forms, varying from a silvery, transparent form through to a red form. It is thought that the colour is determined by habitat, with the ligher coloured fishes being found in clear waters, and the red forms coming from
blackwater. This species is shallow bodied in comparison to its congeners, with its depth fitting into its standard length 2.71 to 2.9 times. There is a black
humeral spot, and females can have a black stripe, with cream edges, running along their
dorsal fin. ==Distribution and habitat==