Diagnosis: A shallow-bodied Paretroplus distinguished from all congeners except P. gymnopreopercularis by the presence of a blotchy, mottled, and irregular pigmentation pattern, the absence of vertical bars on the flanks, and by a fleshy snout that extends rostral to the lips and also ventrally to cover a portion of the upper lip (Ref. 78623). Paretroplus kieneri is distinguished from its sister taxon, P. gymnopreopercularis, by the presence of a more or less fully scaled preopercle, except along the ventral margin, vs. completely asquamate; a pointed and mildly convex predorsal profile, vs. blunt and strongly convex; and a second lacrimal plate that forms a part, albeit small, of the orbit margin, vs. second lacrimal plate excluded from orbit margin; the pigmentation pattern of P. kieneri is conspicuously blotchy, mottled, and irregular, whereas P. gymnopreopercularis is characterized by a weakly mottled and especially uniform chain-link lateral pigmentation pattern, owing to darkly pigmented scale margins (Ref. 78623).