I have an axolotl. They're really incredible creatures, with way more personality and interests than you would expect. They are really soft, and almost have the same density as water, so they can be neutrally buoyant and even swim rapidly like a fish. They're also very sensitive to sharp things; mine recently got a cut from an aquarium decoration, which healed fully over the course of a week. Her previous owner had neglected her and induced tail curl, which took longer to heal (a few months) but did fully heal. I have since adjusted her tank to give it all flat or smooth surfaces, with some variety.