I agree ^
The addiction begins!
Nice new addition, they are hard to say no to. It would be helpful to know the sex to see a picture of the base of the tail, males have a pretty obvious bulge by 17 grams. I also would not be housing two geckos of different size together. For your 6 gram I wouldn't buy anything bigger than a 24 qt tall tub (the same tubs I am currently using for my leachies). A 10 gallon tank can sometimes be a bit much for a small crestie, but it doesn't seem like yours has had any problems. Congrats!