The present study addresses the question of whether or not two guppy species, the Endler’s guppy (Poecilia wingei) and the common guppy (Poecilia reticulata) are able to mate and produce offspring. The question of interest is in the context of the conservation of the Endler’s guppy that occurs only in a limited habitat compared to the widespread common guppy. Female mate choice, male mating behaviors, and possible hybrid offspring of these two species were assessed to determine if the two species will mate and produce offspring. Endler’s guppies’ females did not show a preference for males of their own species, for higher levels of carotenoid coloration, or for larger size in males. Additionally, males of these two species did not exhibit significant differences in mating behaviors. Finally, these two species were capable of producing hybrid offspring. Hybridization in their natural habitats may cause a loss of the Endler’s guppy, which is discussed in the context of the relationship between biodiversity and ecosystem services.