Rivulus robustus Miller & Hubbs, 1974 The Mexican rivulus (Millerichthys robustus) is a species of killifish from the family Rivulidae which is endemic to Mexico where it is found in the Papaloapan and Coatzacoalcos River basins.

This annual killifish grows to a total length of 4 cm (1.6 in).

It is the only known species in its genus, but its exact taxonomic position remains uncertain, as it has not been included in any phylogenetic study.

[2][3] This species was described by Robert Rush Miller and Carl Leavitt Hubbs as Rivulus robustus in 1974,[4] it was reclassified in the monotypic genus Millerichthys in 1995, the generic name honouring Robert Rush Miller.

This Rivulidae article is a stub.