Axolotyl
This is one of the oddest creatures I have ever seen. Most amphibians live on land and water, but this one, Axolotyl, spends its entire life in the water. It never develops lungs like most amphibians do. It keeps its gills, that are located on the outside of the body, throughout its whole life.
The gills are very sensitive to flowing water. 
Axolotyl are endangered in wild, but they breed in captivity and are kept as pets.

"Axolotyl" by stephamelon

Source posted by Julia