Hyphessobrycon axelrodi, the Calypso tetra, is a species of freshwater ray-finned fish belonging to the family Acestrorhamphidae, the American characins. This fish is found in Trinidad & Tobago.
It was named in honor of pet-book publisher Herbert R. Axelrod (1927–2017), who collected the type specimen.
Description Hyphessobrycon axelrodi is a small, iridescent, silver fish with white-tipped dorsal, anal and pelvic fins. It also has a red tail. Females are duller, with faint gray-tipped fins and a dull pink tail.
Distribution Hyphessobrycon axelrodi is endemic to the island of Trinidad. It inhabits low elevations in fresh and brackish waters near swampy areas.
References
http://www.theaquariumwiki.com/wiki/Hyphessobrycon_axelrodi
http://www.aquariumglaser.de/en/fish-archives/hyphessobrycon_axelrodi_en/