External gills

External gills are the feathery, branch-like gills that stick out from the sides of the head on neotenic salamanders like the axolotl, letting them breathe underwater for life.

Full, fluffy gills are a sign of a healthy, well-oxygenated axolotl; gills that curl forward or shrink can signal poor water quality or stress. A true axolotl keeps its gills — an animal losing them may actually be a metamorphosing salamander larva.