Caecocypris basimi, the Haditha cavefish, is a species of cyprinid fish endemic to Iraq, only occurring in aquifers near Haditha. It is found in an underground sinkhole directly under a shrine the only way to access which is a well 5m below the shrine.[2] This cavefish is the only member of its genus. The species is classed as Critically endangered, possibly extinct, by the IUCN, as there have been no records since 1983 despite a comprehensive survey in 2012.[1] The primary threat is water extraction, which has lowered the groundwater level.[1] It is placed as one of the top 10 lost freshwater fishes to be found.[3]
The cavefish Garra widdowsoni is found in the same place and it has also drastically declined, but it is not as rare as Caecocypris basimi.[1][4] The only other known cavefish in Iraq is Eidinemacheilus proudlovei.[5]
The holotype of Caecocypris basimi, collected by Dr. Basim M Al Azzawi in 1977, is deposited at the British Museum of Natural History and other specimens are at the Australian Museum.[6]