An Axolotl’s Frilly Gills Aren’t Just for Looks

Many people think the “crown” on an axolotl’s head is just decoration. It’s actually a set of external gills, an important tool for breathing underwater.

How do the gills work?

Axolotls have three pairs of gill stalks on the sides of their head. Each stalk is covered in fine, feathery filaments. These filaments increase the surface area for absorbing oxygen from the water. Their pink or red color comes from blood vessels visible from outside.

Interestingly, in water with little oxygen, axolotl gills tend to grow bushier so they can absorb more of it.

Three ways to breathe

Gills: the main way, absorbing oxygen from water.
Lungs: axolotls have simple lungs. Now and then they swim up to gulp air at the surface.
Skin: an axolotl’s thin skin also absorbs a little oxygen.

Gills as a “mood indicator”

For axolotl keepers, gills are also a health clue. Gills that stay curled forward can be a sign of stress, for example from water that’s too warm or a current that’s too strong.

In Pumiland, my gills are shaped like flower petals. They spread when I’m happy and fold when I’m shy. So if you see them folding… yes, I’m feeling shy. 🌸