John Arthur Endler is a Canadian ethologist and evolutionary biologist noted for his work on the adaptation of vertebrates to their unique perceptual environments, and the ways in which animal sensory capacities and colour patterns co-evolve.

Poecilia wingei, known to aquarists as Endlers or Endler's livebearer, in the genus Poecilia, is a small fish native to the Paria Peninsula in Venezuela. They are prolific breeders and often hybridize with guppies. These very colorful hybrids are the easiest to find being offered in pet-shops, typically under the name Endler's guppy.