Let me start by saying this is Lilo!
Lilo is about 8 months and I've had her since the beginning of March. She belonged to my uncle along with her sibling, he didn't play with them much and only fed them crickets, no crested gecko diet or anything like that. He dusted crickets every other day and just tossed them into the tank. Both Lilo and her sibling (Stitch) were in the same tank at the time. He got them in October or November and were told they were about 2 months old. Fast forward to when I got them, first thing I do even for the two geckos I already had was weigh them. Stitch was about 13g so he was good, then I weighed Lilo, she was 8.8g. I was startled but already knew she would weigh less because she was very small compared to her sibling, I had some Grub Pie from when one of my geckos needed to gain weight (She was 4yrs and weighed 17g, shes up to 38g now and happy) I started giving her some of this and feeding her everyday instead of every other day which I do with the other ones. She wouldn't eat crickets and sometimes eats worms so she is mostly just having the powdered food but is up to 9.4g. I talked to a guy and Petsmart and he said to put then back together (I separated because of size difference) which I'm hesitant on doing because it's been about 2 weeks or a little longer, he also said I shouldn't bring her to a vet because they cant do nothing. I am pretty new to Crested geckos as I've only had mine since October and December so I need some help. What do you think?