Floating axolotl?

[Lemi]

My axolotl keeps floating. She doesn't always do it, but often when she tries to sit on the bottom, her tail floats. I also notice sometimes when she's floating at the top, her tail is dangling rather than floating with her. Her diet consists entirely of earthworms, her substrate is fine sand (she has never been on gravel), and my other two don't have any problems. One does float, but he never seems to have problems getting to the bottom. The temperature is roughly 60°F. I don't currently have a water quality kit, but it looks fine and I do 50% water changes once or twice a week.
All three are separated, but they get exactly the same treatment.
She has been defecating, but it isn't always completely solid. There is no sign of illness or stress in her or the other two.

 

[Jennewt]

I have one axolotl that floats occasionally - sometimes for days at a time - then goes back to the bottom. I have no idea why. If she's still eating and otherwise looks OK, I wouldn't worry. Unless it goes on for weeks.

 

[Petersgirl]

Sometimes an axolotl's bottom will float because they need to poop - it can also be a sign of constipation, which normally clears up on its own. If it continues for weeks, you may need to fridge or consult a vet, in case they have impacted themselves.

My Galaxy floats when he needs to poop and also randomly floats at night between 9-12, but this is also when he's most active. Floating can also be caused by trapped wind (often released via a yawn, or sometimes through pooping) or, in very young axolotls, it can simply be them learning how to swim (they need to inhale air to float, and thus, to get up to the surface). If it doesn't go on for a long time, seems to be set to certain times or isn't accompanied by any other symptoms, I wouldn't worry

 

[Petersgirl]

PS My axolotl's poops aren't completely solid in that they will come apart when they're hoovered sometimes. Earthworms in particular do seem to produce semi-solid poops, probably because they're so soft themselves (earthworms are the sole diet for mine too). I wouldn't worry overmuch. An eating, pooping axxie is a sign of health ^.^