His growth doesn't look very stunted in those pics rat . Even the largest coastal can be kept in a 6ft enclosure. I think a majority of them can live comfortably in a 4x2x2. My coastal is about 5.5 ft now and he's in a 40g tank with plenty of room. He's scheduled to move into his 4x2 later this year. My 7.5 ft bull snake is in a 4x2 as well.