Right now, I'm using a 15 gallon for my 8 week old female. She is growing like a weed and is a bottomless pit when it comes to food. She eats every 3 days easily and has gone from 102 grams when I got her to 138 grams in 2 weeks. My question is it is starting to look like the 15 gallon is getting small so next week, I'm debating on a 20 gallon long(30x12) or a 40 gallon(36x18). I eventually will get her either an Animal Plastics or give her my red tails 48x23x14 Proline sometime around the end of next summer when I upgrade my red tail to 5 or 6ft cage. I'm mostly just wondering from those who have had baby girls, how fast do they grow and will she last in a 20 gallon long till end of next summer possibly fall or should I just go for the 40 gallon now and be completely safe for sure? Thanks.