They can be kept in a tank long term, just probably not most of our tanks. To keep them you need a lg tank, IMO 300 gal or more, no decor and a deep sand bed for them to dig in. Anything like live rock and or decor would just get in the way. Get a big filter and huge protien skimmer to handle the waste, lighting isn't improtant to them. And they are tropical, the ones here in south FL handle water temps in the 80's with no problem. The question is do you want to devote a huge tank for an animal that will be burried most of its life under the sand. IMO they should be left in the ocean as well, I would geuss that all of the juv's collected die within a few months, they aren't suited for the style of tanks that we all keep.