Boxer Pupfish Cyprinodon simus

Boxer Pupfish were endemic to Lake Chichancanab in Mexico's Yucatan peninsula, one of two known water bodies to have more than one species of pupfish resident. It is now extinct in the wild.

The pupfish in the lake evolved to different niche habitats/diets and the Boxer had a diet of small aquatic invertebrates (and some water surface invertebrates). Introduced Nile Tilapia and Banded Astyanax Tetra out-competed the Boxer Pupfish.

A thorough scientific search in 2024 failed to find any Boxer Pupfish in the lake (one had previously been re-discovered in a 2009 search for the then extinct-in-the-wild species). The last remaining Boxer Pupfish in captivity are being raised by ZSL's Whipsnade Zoo, with some eggs being transferred to Bristol Zoo Project for back up.