Whitefin Pupfish

Strikingly white, one third or more of the dorsal and anal fins in nuptial males, when viewed in clear, shallow water as a brilliant, milky- to pearly-white flag with a proximal, blackened blotch on its posterior margin. Terminal caudal bar strongly developed in adult males. First dorsal fin ray not modified, narrower than or only as broad as the second. Breast fully scaled. Modally 9 dorsal and anal fin rays; 27 lateral line scales; 28 total vertebrae.

Dorsal soft rays (total): 7 - 10; Analsoft rays: 6 - 10

Occur at relatively high elevations (1800-2300 m).