A 10-gallon aquarium can accommodate a single adult axolotl. Axolotls do not emerge from the water, so a land area would go unused. Fill the aquarium to the depth of your choice, but it will be easier to maintain good water parameters when the aquarium is filled, as you would for aquarium fish. A lid or aquarium hood should be kept in place at all times because axolotls have been known to jump out of their aquariums. To make sure they don’t get stressed, make sure there are some hiding places for them. Try not to leave an aquarium light on for longer than an hour a day, because axolotls eyes are on the top of their heads and don’t have eye lids.
The ideal substrate for axolotls is aquarium-safe sand. Axolotls have a bad habit of ingesting gravel and mouth-sized objects if they are available. This can lead to gut impactions and the death of the axolotl. If you wish to use gravel, consider large pebbles instead. Anything the size of an axolotl’s head or smaller can and will be consumed!
A substrate is not essential – many keepers use no substrate at all – but it is certainly more pleasing to the eye in a display aquarium if a substrate is used, and it will also help to keep water parameters stable by providing surface area for beneficial bacteria.