Males of Aphyosemion pseudoelegans differ from all other Aphyosemion species by a diagnostic combination of colouration characters: most prominently it differs from all other species except A. congicum by the almost complete dark red to black dorsal fin versus red dots or stripes on lighter background; it also differs from all other species except A. elegans by irregular narrow vertical red bars, based on confluent dots, on flanks of males (Ref. 91032). It differs from A. congicum by having an asymmetrical coulour pattern of the marginal and submarginal bands in the caudal fin versus colour pattern of dorsal and ventral marginal and submarginal bands symmetrically; A. congicum has only a few red dots on the flanks and an almost dotless anal fin versus many red dots or bars on flanks, anal fin with many red dots or inter radial red stripes (Ref. 91032). Besides the dark dorsal fin, the body colour resembles that of A. elegans, but A. pseudoelegans has an asymmetric colour pattern in the caudal fin versus a symmetric pattern in A. elegans; in general, A. pseudoelegans is more intensely pigmented then A. elegans, often having larger and more red dots on the flanks and a denser red pigmentation of the head; A. elegansalways shows two or more small isolated rounded red dots underneath the eye, whereas in most A. pseudoelegans these dots are larger and irregular and often fused, forming a red streak; in very heavily pigmented A. pseudoelegans, the red dots in the caudal fin may form vertical bars, which is never the case in A. elegans. Both species may show narrow vertical dark red bars on the flanks, but in A. elegans these bars may run all over the flanks, whereas in A. pseudoelegans these bars in most cases only cover the ventral part of the flanks, and dorsally frequently with nearly regular rows of red dots (Ref. 91032).