Desperately need hermit crab help please!

[Melon1]

I have two hermit crabs, and one has been so odd the last week. He’s been crawling around completely naked/shelless and obsessively looking at and trying to get into shells. At first he seemed to get in them ok, but then less than a minute later he’d get back out of it. Now he seems to be really struggling to even get in a shell, his abdomen doesnt seem as flexible and he’s been pinching at his ‘tail’ and trying to pull his abdomen forward and into the shell. I even saw him a few times where it looks like hes trying to eat his ‘tail’ (put it in his mouth). I just hate to see him like that, i know he must be so incredibly stressed without a shell, but he doesnt seem happy with any of them, and now i dont even know if he’s able to get in one. I dont know what to do. I’ve tried buying him new shells, but ive been struggling to get ones a good size for him (loads of them i bought were massive and clearly for land hermits, ive wasted a tonne of money). Nonetheless, he definitely has at least a few that should be suitable for him but he’s not happy with those either. He was in his previous old shell for years, so im wondering if he’s really missing it and wishes he could have his old shell back. However he doesnt seem to fit in it anymore. Im currently in the process of trying to get him some shells that look like his old one. But i have no idea how long it will take to get them shipped to me. I feel like ive been faffing around and wasting so much time ordering shells that have been no good. I just wish i could help him. I will attach some videos to show what he’s been like. Any advice or help would be so greatly appreciated. The parameters all seem fine, so i find it hard to believe that’s what has been stressing him, and my other hermit is completely normal. He’s also not wanted to eat the last few weeks and just seems weak i’ve never seen this behaviour before and just have no idea what’s causing it and what he is thinking and feeling

 

[fishywishy]

It’s probably just old or sick unfortunately. They usually come out of their shells like this when they are about to die. There’s not much you can do about it.

 

[Crabs+Shrimps-69]

How is he doing right now?