Not eating and dehydrated

[frost1375]

I've been having such trouble with one of my males. For about a year now, he's had problems with eating. Last year he stopped eating completely and the vet couldn't figure out what was wrong with him. He had fecals done and the crypto test. We even gave him the crypto medication. He wasn't impacted and xrays showed nothing. So I force fed him for months until he seemed to be maintaining weight. I never saw him eat after that, although he must have because he wasn't losing weight again. A couple months ago, I introduced him to silkworms and that's all he eats now. Because of the holiday season, I couldn't find any silkworms or couldn't get them shipped to me, so he hadn't gotten any for a few weeks. Then I went on vacation for a week and got back and he looked skinny and very dehydrated. I got back December 21st. So he's been skinny since then. I've been soaking him to try to get him hydrated. I finally got some silkworms 3 days ago, but he's only eaten a couple. (He usually keeps eating them until I stop giving them to him) None of my other geckos are having problems so I'm just wondering why this keeps happening to him. I know they slow down their eating in the winter. Do they sometimes starve themselves and not even realize it? I don't want to have to start force feeding him again. How much should he be eating? Thank you in advance for any responses. Also, the temps are fine and they are all on tile... there is nothing in there to get him impacted. Nothing new has been introduced into their environment besides for food.