[1] The body is slender and elongated but the caudal and dorsal fins (especially in females) are short.

When in breeding mood, the male's caudal and dorsal fins are half-bluish black, half-bright orange; similarly, the body is also partly golden.

[1] Poecilia catemaconis is known only from Laguna Catemaco, a freshwater lake in the eastern Mexican state of Veracruz, its tributaries and its outlet.

[1] P. catemaconis is the only Poecilia species in Mexico in which adults are restricted to deep water.

[1] Virtually devoid of aquatic plants (other than sporadic growths of Ceratophyllum and Nymphaea), the lake is also home to populations of Dorosoma petenense, Astynax fasciatus, Vieja fenestrata, and fellow livebearers Heterandria bimaculata, Poeciliopsis catemaco and Xiphophorus helleri, as well as Crocodylus moreletii.