In almost all places, different Cyprinodon species do not overlap in their range, but there are two notable exceptions and one of these is Lake Chichancanab, which is inhabited by C. maya, C. beltrani, C. esconditus, C. labiosus, C. simus, C. suavium and C. verecundus (the other place where several Cyprinodon species live together are lakes in San Salvador Island, the Bahamas).

Living together, the Cyprinodon species in Lake Chichancanab have diverged into different niches.

In Lake Chichancanab, however, C. maya has become not only the largest species in the genus Cyprinodon, up to 10 cm (3.9 in) long, but also the only that catches and eats whole fish (C. desquamator of San Salvador Island is a scale-eater).

[5] Among the endemic Cyprinodon species in Lake Chichancanab, only C. beltrani and C. labiosus still occur in some numbers in their habitat, while the remaining are virtually—if not fully—extinct in the wild.

[4][6] The primary reason for their decline is introduced species, notably the Nile tilapia and the tetra Astyanax fasciatus.