Simpsonichthys alternatus (Costa & Brasil 1994)

Bars on anal and caudal fins of male; red distal bar on these. Anal fin of female long, spatulated, and long posterior process of occipital, terminating in narrow posterior extension. Males with short to minute filamentous rays on tip of dorsal fin; dorsal fin pointed, with 6-8 bars through the whole fin; anal fin rounded; flanks with reddish gray bars. Dorsal-fin rays 18-22 in male, 14-17 in female; anal-fin rays 21-24 in male, 18-20 in female; caudal-fin rays 23-24, caudal fin subtruncate in male, rounded in female (Ref. 49550).

Dorsal soft rays (total): 14 - 22; Analsoft rays: 18 - 24; Vertebrae: 25 - 27

Bottom spawner, X months incubation (Ref. 27139).

Simpsonichthys alternatus is a species of killifish from the family Rivulidae. It is found in the São Francisco River basin, Brazil in South America. This species reaches a length of 3.9 cm (1.5 in).