This is true. I think the 18x18x12 is a little overkill unless you have a large female. For a male it is way more than enough. My ornate is in one 18x18x12 and he only uses 45% of the whole thing hahaha, buddy boy does not move for over a week sometimes. I'm thinking of transfering to my 10g soon and use the 18x18x12 for my growing pyxie.