Author: Valenciennes, 1837
Comments: Feeds mainly during the daytime, though some large fish (15-20 cm SL) extend their foraging activity to dusk (about 1800-1900H).  Night is spent sheltered among vegetation.  Small-sized to medium-sized fish (7-10 cm) are solitary and patrol feeding territories (3-4 square m.) in a way similar to that reported for the scale-eating <i>Catoprion mento</i>.  Stalking with some use of plant cover is a frequent mode of hunting employed by <i>S. marginatus</i>.  It approaches its prey with a slow, stealthy movement from behind or below.  It strikes its prey on the tail or anal fin, of which a piece is clipped out with a jerking motion of the body.  This clipping is audible underwater.  Lurking is also employed during daytime (Ref. 9080).