You should start with
www.axolotl.org as this is the BEST! place online to get information.
But basically:
Tank for one adult, a 20gallon long (~30 inches), plus 12 inches per additional adult, with emphasis on floor space, not water column.
Filtration is important. Canister filters are best. Keep current to a minimum, as well as heat output from the filter.
Substrate: No substrate is best. Sand is next best. Large rocks/Slate is adequate. Gravel is inappropriate and can cause impaction and death.
Feeding: they're hungry all the time. Adults should be fed every 2-3 days, depending on temperature and the like. Chopped earthworms, pellets, bloodworms, etc, all make good food.
Behavior: They'll chew on each other. They're not especially bright, and bite anything that moves. Females are generally fatter. Males have a larger cloaca. Behaviorally, there's no difference.
