Advice?

[uhhh]

Hi, I have had my leopard gecko for 2 months and he is 9 months old. Over the past 3/4 weeks he hasn't been interested in his food whatsoever only eating a couple of bugs each week. I offer gut loaded crickets and mealworms but after eating 1 or 2 he just seems to lose interest. I also noticed his tail has shrunk in width so I am calling vets tomorrow for advice bust just wondering if anyone has any ideas why he doesn't want to eat? He still seems pretty happy; he enjoys climbing and being held but only inside the tank so I don't take him out a lot. Attached photo of when i first got him vs now. TIA

currently:

when I first got him:

 

[acpart]

It's hard to know exactly what's going on. Here are some things to check: Is it warm enough on the bottom of the enclosure on one side? Is he normally active? I think it might be a good idea to take him to the vet. Make sure they test him for the usual parasites (pinworms) and also for cryptosporidiosis (I'm not saying he has this, but it's good to do a test just in case).

Aliza