There are two things to know about these large inverts before buying one. First thing is their diet, it is a popular misconseption that they are pure carnivors but this isnt true, the bulk of their diet should be made up of vegetables like peas and green beans with meaty foods only being given twice a week at most. Secondly they are a coldwater tropical animal, in temperatures above 70 the lobster will moult more often than it should which leaves it open to infections while in its soft state and a deficiency in calcium.
They should be kept in a species tank only since they will prey upon anyfish which is small or slow enough to be caught, ones that are not may see the lobster as food, and since most species can easily grow to 12" a minimum of a 48x18x18" tank should be used.