Alestes stuhlmannii is fusiform with a terminal mouth and a snout that becomes more blunt in larger individuals (Ref. 79648). The dorsal fin is in the middle of the back, and the adipose fin is closer to the caudal than to the dorsal fin (Ref. 79648). The anal fin base is much longer than the dorsal fin base (Ref. 79648). The body is covered with large cycloid scales which extend onto the bases of the anal and caudal fins; there are no scales on the head and none on the supraoccipital crest (Ref. 79648). In preserved specimens, the flanks are usually darker dorsally than ventrally; a thin, dark line runs along the flank from the posterior edge of the opercle to the base of the caudal fin rays; it does not follow the lateral line and is not confined to a single scale row (Ref. 79648).