When it is fully grown you will probably want an 8 footer. They grow to a solid 3 feet in the wild, 2-2.5 more likely in a tank. But it takes a while. He has maybe gone from 11" to 14" since I got him 5 months ago. He is still relatively small. They sleep during the day mostly on rockwork. You want some live rock but not too much where they have no space. Once the lights go out or you turn the blue spectrums on very low, they get really active.. And it gets active during feeding too of course. I wouldn't sell it to anyone who has a tank smaller than the one he is in now. Not trying to be a snob but it's not right to the fish. So a 6 foot 150 gallon tank at least and it's yours.