A swordtail (Xiphophorous helleri) is a vibrant freshwater fish native to Central America, particularly Mexico and Guatemala.

It is slow-growing and can be pruned heavily once the new growth has hardened. It is available in a wide variety of shapes and sizes, including narrow and upright (‘Sky Pencil’, shown here), rounded ( ...

There is the Taita thrush (Turdus helleri), also known as Taita olive thrush, an endangered bird from the family of thrushes (Turdidae). Conservationists are using the thrush as the flagship ...

Aldridge, R. D. 2002. The link between mating season and male reproductive anatomy in the rattlesnakes Crotalus viridis oreganus and C. v. helleri. Journal of Herpetology 36:295-300. Aldridge, R. D.