HCA: Hermit Crab Association

We adopted a hermit crab from a friend in December. They had him for a year prior to us taking him. They didn't take the best care of him (only pellets for food, low humidity, no salt water, painted shells). We let him get adjusted and once he was adjusted we upgraded him to a big tank! He loves his tank and is usually really active and always climbing and moving around. He is in a 29 gallon with a glass lid, humidity is always around 80-90%, temp ranges from 75-80, he has a mixture of coco fiber and sand for substrate that is deep enough for him to molt if necessary, he eats a varied diet from the recommended food list, he has salt water now, and plenty of shells to choose from! He has a little hanging coconut hut that he loves. About a week ago, he went in the coconut hut and hasn't come out. I noticed that he isn't even out of his shell like he normally is. I try not to disturb him because I don't want to cause stress. I have checked on him a little bit by touching his shell to make sure he moves and he does but what could cause this? I miss seeing him out and moving around and my heart hurts knowing he may not be well

He could be getting ready to molt. Do you know when his last molt was?
Are you sure he isn't coming out at night when you aren't watching?

I'm pretty positive he isn't. He is a really messy eating and gets his water really dirty and both always look untouched. I get up atleast once a night to pee and always check and never see him out I do know he was LOADING up on food shortly before this. He was eating SO much more than normal. So maybe he is going to molt? He's never molted the time we have had him and the previous owners said in the year they had him he only molted once or twice. If he is going to molt is it normal for them to slow down like this before burying?

I agree with Curly sister - sounds like he is getting ready to molt. If he is the only crab, it sounds like he is going to pull a surface molt; which isn't healthy.

How deep is your substrate?
What kind of salt are you using to make his saltwater?
Are you using a dechlorinator?
Is he getting plenty of calcium?
Is he getting oils and fats?

He does get dechlorinated water and salt water, daily. We make his salt water with instant ocean salt. We have been carefully following the food pyramid off of this site to make sure he gets a good balanced and varied diet. I just measured his substrate it's only 4 inches deep, I'm reading it should be atleast 6 inches. Maybe that's the issue I have never noticed him even trying to bury though. I've noticed spots where he has dug before but never deep. I really hope he's okay 🥺

Update on Crabby! He survived he was definitely doing a surface molt. My husband and I found out his substrate was too wet. We fixed it and covered his tank with a towel. He never buried himself during this molt, i think by the time we addressed the substrate issue, he was too far along in the process. But he survived and just last night he finally emerged again 🥹 He has eaten and soaked in his water dishes!

That's good to hear!
An easy test to see if the substrate moisture level is good - stick something like a chop stick down into the sub, right along the glass, to the bottom, then remove it. If you can see that the sub stays in place and there is a nice hole, your sub is good! If there is any water pooling in the bottom of the hole, it is too wet. If the sub collapses and the hole doesn't hold, your sub is too wet.

Good to know! I will try this out, thank you!!