I just came to the forum to search this same issue!

I found a post from Oct.7, 2007, in which someone asks about their leopard gecko that has fluid under the armpits, and someone else responded that it wasn't anything to worry about and that it sometimes happens with overweight geckos who are aggressive feeders.

My leopard that has the fluid under her armpits is plump, and I was wondering if her weight was a factor.

I'd love to hear from anyone who knows more about this issue.

I guess I'll just scale back my leopard's food a little.