The Kızılırmak toothcarp or Sultan Sazlığı toothcarp (Aphanius danfordii) is a species of killifish belonging to the family Cyprinodontidae. It is endemic to the Kızılırmak River and the upper Seyhan River drainage systems and is now restricted to a few locations in the Sultan Sazlığı marshes. Though little data is available, the population of the fish seems to be declining. The International Union for Conservation of Nature has rated its conservation status as being "critically endangered" and fears it may become extinct in the wild if the drainage of the marshes continues.