Why is my Leopard Gecko Not Eating?

For one, geckos will naturally go off food for long periods of time. This is completely normal, and unlike most typical mammalian pets, they don't require food every day, or even every week for that matter. In the wild they will even go the long cold season without eating at all. Naturally, their activity is very low during this time as well. They are well adapted to this process and we must consider this natural behavior when we make assessments to their health. A leopard gecko going a few weeks without food will not hurt them at all. I have seen them go a few months and then bounce right back. Extreme thinning of the tail and pronounced backbone are signs to look out for — not how many mealworms they've eaten this week. All this being said try to relax as stress factors are typically the biggest issues you will face in getting them back on food. 

Don't panic! This happens regularly.  Most geckos that don't eat right away are usually doing so because of stress due to shipping, new environment, different food/supplementation, and especially due to extra contact and activity within the enclosure.

Your gecko has been eating mealworms (younger geckos) out of a shallow dish exclusively up until this point. I recommend not feeding the gecko right away (2-3 days) when first acquired to help with the stress going down and the prey drive going up. If the gecko isn't taking food after a week then I recommend putting the bowl of regular mealworms in front of the hide. Leave them in a day and then take them out completely for two. Then put fresh ones in for another day and repeat the process. This keeps the gecko from getting overstimulated by food being constantly in their face. I have never seen a gecko not eventually take to food this way as long as the other conditions and stress factors are correct.

It is so very important that you eliminate all stress factors at this time. This especially means no holding or direct contact with the gecko until it is fully adjusted and eating well on its own.