Put the summary of the bug you're having here
Pet axolotls vanished.
What I expected to happen was...: they would be where I left them and the opportunity to interact with them.
Describe what you thought should happen here
I am not sure if it would be possible to get them back, I received no death message from the one nametagged, no hidden axolotl. They should have not vanished.
What actually happened was...:
Describe what happened here
3 were missing.
Steps to Reproduce:
1. Put a step by step guide on how to trigger the bug here
2. ...Have an axolotl enclosure with water, and décor in an inescapable area the only entry and exit being a (closed) fence gate
3. ... Leave to go mining or lighting up caves for several Minecraft days then return.