For aquarists perhaps more useful are the subtle differences in colour pattern with P. simulans differing from both P. innesi and P. axelrodi in possessing a greener (vs. bluer) lateral stripe which covers more (vs. less) of the eye/head and extends to the caudal-fin base (vs. terminating anterior to caudal-fin base), a lesser (vs. greater) amount of relatively duller (vs. brighter) red pigmentation on the flanks.

The taxonomic history of all three species is complicated with earlier authors such as Géry (1960, 1977) ten…