As of July 2017, the International Union for Conservation of Nature (IUCN) listed 1,000 critically endangered fish species, including 87 which are tagged as possibly extinct.[1][2] Of all evaluated fish species, 3.0% are listed as critically endangered. The IUCN also lists four fish subspecies as critically endangered.
Of the subpopulations of fish evaluated by the IUCN, 20 species subpopulations and one subspecies subpopulation have been assessed as critically endangered.
Additionally 3191 fish species (21% of those evaluated) are listed as data deficient, meaning there is insufficient information for a full assessment of conservation status. As these species typically have small distributions and/or populations, they are intrinsically likely to be threatened, according to the IUCN.[3] While the category data deficient indicates that no assessment of extinction risk has been made for the taxa, the IUCN notes that it may be appropriate to give them "the same degree of attention as threatened taxa, at least until their status can be assessed".[4]
This is a complete list of critically endangered fish species and subspecies evaluated by the IUCN. Species considered possibly extinct by the IUCN are marked as such. Species and subspecies which have critically endangered subpopulations (or stocks) are indicated.