molting & daytime/nightime question

[MarshmallowMama]

We are first-time crabbers, and have 4 small hermit crabs we love. We have referenced this site about a million times to make sure we set up the crabs' home properly and are being "good crabbie friends" (as we like to tell our daughter). Since neither my husband or I have ever owned hermit crabs before, we're not sure what a happy crab looks like. One of our crabs was extremely active for the first few days we had him. He crawled everywhere, climbed everything and ate well. Then he buried himself a few days ago and we haven't seen him since. I have resisted the urge to dig him up, remembering what I read about leaving them alone when they do this. Since I didn't recognize the molting behavior beforehand, he made it under the substrate before we could put him in the iso tank. Now that he's there, do I just leave him alone? We had decided to leave him there and then keep a close eye when he comes out to make sure he stays safe from the others. Is this correct?
Also, the other three crabs were acting the way we'd expect nocturnal creatures to act: they were fairly inactive during the day, but then crawled around a lot at night. For the past few days, however, they have been pretty active during the day, too. And even when they are not crawling around, they are sitting on the driftwood or on top of the rock with their heads out of their shells, and often only retreat back into their shells if my daughter makes sudden movements near the tank. But then they come out again, and they climb around or just sit and look around. I made sure the tank is not too hot, and it's nice and humid without being stifling. What is wrong? Shouldn't they be sleeping or something? Don't get me wrong. I love being able to look at their little faces, but I worry that they aren't resting because they feel threatened or something, and aren't getting enough rest. I don't want them to be unhappy crabs.

[Wai]

You are right to leave the first hermit crab alone.

Hermit crabs have random sleeping patterns. I wouldn't say that hermit crabs are nocturnal, but that doesn't mean that they're always active during the day. In other words, hermit crabs are active whenever they want to.

Your hermit crabs withdraw back into their shells upon seeing your daughter is normal behaviour. I've had some of mine for over a year now and they still "flinch" upon seeing me approach the tank.

I think your hermit crabs are still getting used to their new home. On the first day, they are actively exploring your new home, then they slow down as they get used to it. From what you've told me so far, I wouldn't worry too much. You're doing well.

[ladybug15057]

Welcome to HCP!
You mention the temp and humidity levels, do you have gauges to monitor these? Would you happen to know the substrate temp too on the warm and cool side of the tank?
Being new, they should be left alone for a few weeks to de-stress.

[mamaturtle2000]

You sound like you're doing pretty well, congrats! My crabs tend to decide when they want to be active too,lol. Yeah, Wai is right (of course,lol) about leaving the possible molter alone, but if you are really worried, you can cut the top off a 2 liter bottle, wash and dry it thoroughly (throw away the cap or you can use it as a water dish, depending on the size of the crabby) and push it down over where your crab is buried. Make sure you push it down all the way to the bottom of the tank. This will protect them from any other crabs that may try to get at them if they are molting. You can search to see what the consensus is on putting food in there with them. Best of luck!

[CrabbyJo]

Awesome job researching, welcome to the addiction of hermit crabs.

Mamaturtles suggestion is a good one, I've read it many times. In practice though, I've had some of my own misgivings about it so never used it. My crabs have all molted within the tank, and done fine (except for one, who may have been disturbed by another extremely actively digging crab), without any isolation. They have a huge variety of food though, lots of seaweeds and protein and calcium.

If you do choose to use the soda bottle method, you can do it with the narrow top on, or you may want to trim it down so it's just a large tube (no narrowing) since it may become warmer or more humid within the bottle with only the small pouring hole open. I may be a little paranoid, but that's my thoughts.

I would also, yes, put small lids of both waters and a small dish (a small plastic bottle lid will work great, like what was on the 2 liter bottle) of food as well, such as seaweeds, calcium (crushed eggshell or cuttle bone) and protein (dried shrimp works great). He could come up mid-molt for sustenance, so you don't want him closed off from that.

If you choose to let him be, then don't worry too much. Just watch the tank regularly, and if he does come up when he's still pink (mine all stayed below the surface to harden), just make sure the other crabs can't get to him.

[Wai]

A warning about the soda bottle method: make sure there are no hermit crabs in the way of the bottle when you push it down. There was a case where a crabber tried pushing the soda bottle down to isolate a suspected moulter, but there was another moulter in the path of the bottle - and it died after almost being sliced into two.

[mamaturtle2000]

OMG Wai! Brutal,hh! I thought you were talking about me till you said it got sliced in half, as I did accidentally trap Toki in w/Pikachu in her ISO. But I caught him emerging and was able to get him out of there.