HCA: Hermit Crab Association

One of my crabs has been leaving its shell multiple nights in a row. More details below. Any help/advice would be greatly appreciated! Thanks in advance!


1. What kind of substrate is used in your tank and how deep is it?
5:1 ratio. Sand:cocofiber. It's 4 inches right now. That'll change soon though to 6 or 7.


2. Do you have gauges in the tank to measure temperature and humidity? If so, where are they located and what temperature and humidity do they usually read?
Yes. It's near the middle off the substrate. It's usually low 80s for temperature and mid 70s for humidity. I'm trying to get the humidity up a little bit to the 80s.


3. Is a heat source used in the tank? If so, what?
There's a heat mat on the back of the tank, but since it's summer and the cooling in the room doesn't work, I don't need it on at the moment.


4. What types of water are available (fresh or salt) and how is the water treated (what brands of dechlorinator or salt mix and what ratio is used to mix it)?
There's both fresh and salt water available. I use API to dechlorinate the water and I use a bottle of hermit crab saltwater from the pet store. I plan to switch to Prime and Instant Ocean soon.


5. What kinds of food do you feed and how often is it replaced?
I give them a varied diet. Fresh produce that I replace daily, and some nuts, seeds, worm castings etc.


6. How long have you had the crab and what species is it, if known?
I've had both crabs for almost 3 months. They are both purple pinchers.


7. Has your crab molted, and how long ago did it happen?
I'm not sure. A few weeks ago, it went underground for a week or two. I don't know if it was molting or if it dug underground for another reason. Nothing seemed different when it came up.


8. What type of housing are the crabs kept in, what size is it and what kind of lid is on the housing?
They're in a 10 gallon glass tank with a mesh lid with a piece of acrylic taped to it. I'm currently getting a custom lid made for a 47 gallon so once that lid is made, they'll be moved into that bigger tank.


9. How many crabs are in the tank and about how large are they?
There are 2 and they're about quarter sized. Maybe a little bigger.


10. How many extra shells are usually kept in the tank, if any?
10 right now. They're all natural. The shells they're in right now are painted, and I can't wait until they change into a natural one.


11. Have there been any fumes or chemicals near the crabitat recently?
Nope!


12. How often do you clean the tank and how?
I haven't done any deep cleaning. I clean the pools every couple of days and take out old food every day or so. My crabs are neat and haven't made any messes at all.


13. Are sponges used in the water dish? If so, how are they cleaned?
No.


14. Has anything new been added to your crabitat recently?
Not really. I do move things around though because it's difficult to take the pools out without moving some things.


15. Is there any other information you would like to share that might be helpful (anything that is regularly part of your crab care, playtime, bathing, etc.)?
The tank right now is not very great. They have the bare minimum, but once I get a bigger tank set up, everything will be much better for them. More hiding, climbing, activities etc. I've also observed no aggression between crabs at all. The one that's thriving sometimes like to sit right next to the one I'm worried about, but there's no fighting at all.


16. Please describe the emergency situation in detail.
One of my crabs have been leaving its shell once a night. It's been going on for a few days now. Maybe 4 or 5? Before this stuff started happening, it seemed to be doing fine. Eating, drinking, moving. Since it started happening, I haven't noticed it eating or drinking. It doesn't move while in the shell, but when it leaves, it moves around a ton with no interest in the other shells even though they're the right size. I've looked the crab over. It looks fine. It's a rusty red color. No mites. No cloudy eyes. No missing limbs. I use the mug method to get it back into the shell. It refuses to go into any shell other than it's original painted one. I'm not sure what's going on. Is it stress? Will things get better once I move them into the bigger tank? Is there something else I should be doing? Thanks for any help you may have!

Your tank conditions sound good - it has everything that a basic tank needs.
Sometimes crabs have gone thru so much before we get them, that they are not able to recover even if our conditions are perfect.
A crab will drop it's shell when it is too weak to carry it. What type of shell is the painted one? What types are you offering?
Do you feed animal protein? I would add some high energy foods, like peanut butter and honey to see if you can give him a boost.

The painted shell is a babylonia shell. Most of the shells I have are turbo ones. I have a babylonia shell that is a tad bigger, and I'm looking for another one that is the same size as the painted one. I also have some shells with D openings. I will definitely try some animal protein. We don't currently have peanut butter or honey, but I'll make sure we get some soon! Is there a specific way I should feed the honey and peanut butter?

Another thing to add: Every day it takes longer for the crab to get back into the shell. Today it's been 9 hours so far. It used to only take 1. I hope this situation is salvageable.

Thanks so much!

I am sorry to say it, but a crab leaving it's shell this many times and for longer periods is not a good sign.

They do need animal protein daily, and foods with calcium on a regular basis as well (many of us leave a cuttle bone or egg shells in the tank all the time, they don't get moldy like other foods). You can just put a bit of honey in something like a bottle cap. Same with peanut butter. That way it won't get into a big mess in a food bowl.

It's hard because we can't run any diagnostics on our crabs, so we don't know exactly what's going on. Crabs are susceptible to what is broadly known as 'post purchase syndrome' or 'post purchase death syndrome' from the time we get them until at least their first molt with us.

That's what I was afraid of I'm keeping an eye on it and we'll see what happens. Hopefully some honey and peanut butter will help at least a little. Fingers crossed.

Update. I'm very stressed out and worried. It's been over a day since it was last in its shell. I gave some honey in a small bottlecap. I think it ate it, when I checked again, the bottlecap had some water in it from the bottom of the mug, but there was no sticky residue from the honey. Since it's been so long, I found a plastic container, put some holes in the lid, moved the crab into the container and placed the container in the tank. I put some quinoa and pecan pieces in the container in case it gets hungry. I'll try some more honey tomorrow. It's been sitting in the opening of one of the turbo shells that I put in the container but it's not completely in the shell.

Any advice?

I have never manually re-shelled a crab, but can you try that? It's kind of a last ditch effort to get them back into a shell. Is it a polished turbo - like a lighter one?

I'll try that. It is not polished. It looks kind of rough like it was floating in the ocean for a while, but the inside is still smooth.

The crab passed away last night
Thank you so much for your help. I'll be taking extra good care of my remaining crab now and I'll get him some more friends really soon

I am sorry to hear that. Sometimes we do everything correctly and they are still unable to overcome what they went through prior to us getting them. Your tank sounds really good, don't think that you need a fancy or extravagant tank in order to have healthy happy crabs - basic tanks provide everything they need, and the rest is honestly more for the humans than the crabs.
Crabs are okay alone, so don't feel you need to rush into getting more asap. Depending on where you live, check out our adoptions section - if you can find someone giving away their crabs, you will know what the conditions were like prior to you getting them, which will of course increase chances of survival.