I have a 3 1/4" leopard gecko that doesnt seem to be eating. He looks too thin, thin tail. The other two geckos in the enclosure eat well and are excited to eat. He generally is just standing around stiff looking with eyes closed. Its been going on for about a week and im getting nervous.

Guess if I'm gonna be keepin' her I should read up on em eh? Thanks for any help you might be.
. Just to be safe. And Yes'm I have been readin' up on the Leos.