Ameca basin

The butterfly goodeid, Ameca splendens, is a livebearer from the Río Ameca drainage in Jalisco, Mexico, and the neighbouring Sayula valley. Often referred to as extinct in the wild, it still survives at a few localities, and strong captive populations exist in the hobby. As in other goodeids, the developing young are nourished by a structure known as the trophotaenia. Males can be quite aggressive, and it is better kept in a species set-up.

The green swordtail, Xiphophorus hellerii, is a livebearer native to southeastern Mexico, Guatemala, Belize and Honduras. Among the world's most recognisable aquarium fishes, it is ubiquitous in the trade, where selective breeding and hybridisation with X. maculatus and X. variatus have produced a bewildering array of ornamental forms. The name is often misspelled X. helleri.

The tequila splitfin, Zoogoneticus tequila, is a goodeid endemic to the Río Teuchitlán in the Río Ameca headwaters of Jalisco, Mexico. Thought to be Extinct in the Wild when described, it has been the subject of a reintroduction project begun in 2015 by the University of Morelia, Chester Zoo and the Goodeid Working Group. A nippy livebearer, it has few suitable tankmates and needs space for females and subdominant males to escape breeding males.