There are 5 species in the genus with most being found in Cuba.

References:

1.  Costa W.J.E.M. (2011). “Phylogenetic position and taxonomic status of Anablepsoides, Atlantirivulus, Cynodonichthys, Laimosemion and Melanorivulus (Cyprinodontiformes: Rivulidae)”. Ichthyological Exploration of Freshwaters. 22 (3): 233–249.
2.  Huber, J.H., 2012. Reappraisal of the Phylogeny of Rivulus and its Allied Focused on External Characters. Killi-Data Series 2012: 9-25.
3. Ponce De León, José Luis; León, Gunnary; Rodríguez, Rodet; Metcalfe, Cushla J.; Hernández, Damir; Casane, Didier; García-Machado, Erik (2014). “Phylogeography of Cuban Rivulus: Evidence for allopatric speciation and secondary dispersal across a marine barrier”. Molecular Phylogenetics and Evolution. 79: 404–414. doi:10.1016/j.ympev.2014.07.007. PMID 25050928.
4. Silva, Rodet Rodriguez (2015). “Rivulus berovidesi, a new killifish species (Teleostei: Rivulidae) from western Cuba”. Zootaxa. 3949 (2): 289–96. doi:10.11646/zootaxa.3949.2.9. PMID 25947808.

Rivulus cylindraceus
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