Hi, as babies you can keep them in small critter keeper or a ten gallon divided into 2. after a little abit you can move him into ten from the keeper or remove the divider and give him the space of the 10. Some people will keep them in ten gallons their whole life depending on the size and how active it is. If he out grows the ten I wouldn't recommend anything larger then 20 Gallon long. I have recently put my female albino cranwelli into a 20 tall because she was showing signs she wasn't happy anymore, ever since the change besides the settling in she is now fine. And my girl is very active for pacman I believe so she needed the room.