I didn't really like all the frail parts on the other axolotls posted here so I designed one where the arms are tucked back like the swimming animation and the tail where the keychain connection is is extra thick.

The STL posted is 1 pixel = 1mm. The picture shows a 1 pixel = 2mm print (left) and 1 pixel = 1.5mm print (right). It prints good at the default scale without support just beware that you need a really small keychain loop. The bigger the axolotl, the more likely you are to need supports.

Creality

Ender 3

No

Ender 3 V3 SE