HCA: Hermit Crab Association

I've owned my hermit crab for a few years now, but within the past 4 months, he's been acting a little strange. He has buried himself 3 times within the past 4 months, staying underneath the sand for up to a month at a time. He has come up each time looking just fine, eating and drinking normally too, but I'm worried that something might be wrong with him. I've never seen this sort of behavior before. I know for a fact that he's not just coming back up at a night. He stays buried the entire time. Does anyone know what could be up with him?

Edit: Also, nothing has really changed during this time. No new crabs introduced, no changing tanks, no new changes of any kind. The temperature and humidity seem fine as well. He has had successful molts in the past, too.

you have the substrate smoothed out at night so you don't see any tracks in the morning to double make sure he isn't pulling a fast one on you? I have had a crab that has done that but it has done it for weeks at a time, he will go down and be down for weeks i will think o.k. he is molting now. Then boom he comes back up for a few days, eats drinks, acts fine, then all the sudden he is gone again! He will pull this crud on me several times before he stops coming up all together and then he was gone for 2 and 1/2 months and now he is up with the rest of his buds and just all over the place. was his salt water deep enough to get in? I know it's said they like to get in it and soak before a molt & it helps them , maybe he was having a hard time with this molt ? If he seems fine now I wouldn't stress over it.

Glad to hear that this behavior isn't completely abnormal.

I haven't smoothed out the sand much, because I normally hear my crabs clacking around at night, so I figured that would be my signal. Also, currently a shell is blocking the entrance to his little hiding place, and that hasn't been disturbed for quite sometime, so that was another "signal". I'll try it though. I'll be surprised if he has been pulling a fast one on me!

The last time he surfaced (about 2 weeks ago), I found him sitting in his salt water bowl. I gave him some fresh to hang out in (he can submerge), and then shortly after that, he went back down again and I haven't seen him since.

How big is he? Because small or teeny crabs can molt alot, really fast. My teeny, George, has molted four times since August. His shortest one being less then a week, his longest being three weeks, and now he's a small!
Have you checked for needle feet? Or was he displaying molting signs before this happened? (ashy exo, excessive drinking/eating) He might not be molting at all, he might just like it underground! I know some people, me included, have crabs that almost never surface, but they aren't molting, they're just being little stinkers
Another possibility is that he's trying out different spots and different tunnels before he decides which one is the best to molt in

He's small enough to fit in the palm of my hand, but I wouldn't say he's super small. I didn't have a chance to check for needle feet or anything when he surfaced a few weeks ago, but he looked "fresh", if you know what I mean; like he had molted. He didn't exhibit any molting behavior before that.

It just seems weird since he was never like this before. Like I said, I've had him for a few years, and it's not like him to be underground so much. I have no idea why he's doing this so suddenly unless it has something to do with molting.

I've had new crabs molt like crazy, but never one that's been around for a while. My crabs have a history of molting and going down a week or two later and molting again, til they hit large size, then they chill out. And I know they molted because their color changed every time.

my new crab that I got in Jan that had went down for like a month and 1/2 and was just up for less than month is down again..sigh...when I got him his color was bad looked cruddy, when he came up he looked better, now he went down again.. I would say he is a med sized crab. before he down the first time they were very shy, weak, didn't move around a lot, I put food by them, then they started eating acting normal then they went under. made to think they were molting and when they came up they looked a lot better. when he went down this time he was fine to. so he could be doing an other molt?? they come from bad conditions!