species are threatened or extinct according to the IUCN and the U.S. Fish and Wildlife Service Vulnerable – bold characodon, darkedged splitfin, Goodea gracilis, Allotoca dugesii Endangered – bluetail splitfin, rainbow characodon, relict splitfin, Allotoca diazi, Manse Spring killifish Critically endangered – blackspot allotoca, Chapultepec splitfin, highland splitfin, Balsas splitfin, Tequila splitfin Extinct in the wild – butterfly splitfin, golden skiffia Extinct – Ash Meadows killifish, Parras characodon, Raycraft poolfish, Pahrump Ranch poolfish Life cycle and evolution The majority of Goodeid fish are viviparous, typically giving birth to live young. The family includes a number of popular aquarium fish, for example the redtail splitfin Xenotoca eiseni. Recent phylogenetic studies have put the age of this family at approximately 16.5 million years, with the majority of divergence occurring in the Miocene period. The speciosity of this family can be attributed to historical volcanic and geological disturbance in this region, which created suitable conditions for allopatric speciation of the fish. Genera The following genera are included in Goodeidae: Subfamily Empetrichthyinae – springfishes and poolfishes Crenichthys – springfishes Empetrichthys – poolfishes Subfamily Goodeinae – typical goodeids and splitfins Allodontichthys Alloophorus – Bulldog goodeid Allotoca – typical allotocas Ameca – Butterfly splitfin, butterfly goodeid Ataeniobius – Striped goodeid, bluetail goodea Chapalichthys Characodon – characodons Girardinichthys Goodea Hubbsina Ilyodon Skiffia – skiffias Xenoophorus – Relict splitfin Xenotaenia – Leopard splitfin Xenotoca Zoogoneticus References Viviparous fish Freshwater fish of Mexico Freshwater fish of the United States Ray-finned fish families Taxa named by David Starr Jordan