my pond is strictly for koi. have a 65 gallon bowfront aquarium with 2 golden, 1 black, 1 white and 1 wild colored. wouldnt think of putting them in there, besides not cold enough. about half the depth of the pond is under ground and probably total invested would be $600. i always tend to over filter my aquariums and my pond. also have a diamondback terrapin turtle from south carolina. havw a hollow fake log about 10 inches long in with the axolotls. waiting for 1 to climb half way straight up a hole in the log, will post if get the chance at 1 axolotls doing it again