Allodontichthys is a genus of livebearing splitfins in family Goodeidae, endemic to river systems of west-central Mexico. As with other goodeids, reproduction is internally fertilized and viviparous, with embryos nourished through a placenta-like trophotaenial structure rather than a yolk sac, and species are typically restricted to specific spring-fed rivers or tributary systems, which leaves them vulnerable to localized habitat disturbance.
The atlas covers all four described species - the whitepatched splitfin (Allodontichthys hubbsi), finescale splitfin (A. polylepis), Tuxpan splitfin (A. tamazulae), and bandfin splitfin (A. zonistius) - and every one carries a threatened IUCN status: one Critically Endangered, one Endangered, and two Vulnerable, with all four flagged for CARES conservation priority. That makes Allodontichthys one of the most consistently at-risk genera in the atlas's livebearer section. It has some presence in the specialist goodeid-keeping hobby, where dedicated aquarists maintain captive populations partly as a hedge against further decline in the wild, but it is not a mainstream aquarium fish.