HCA: Hermit Crab Association

I have a crab that I would say is at least golf ball size and I believe he is trying to molt. However I am worried because I haven't seen him move in a few days (I can see through the glass on the underside) and there is no response of moving when i gently tap the glass either. I had a smaller crab go down to molt like this and she molded over and had died (definitely had the death stench) and was similarly still and I didn't dig her up until waiting for awhile because I thought it was part of her molting. She had a nice pocket to move around in the substrate and everything. I've had Ranger since September of last year and its his first molt and I'm worried that what happened to my smaller crab might happen to him as well. I think I might have heard him chirping but I'm not sure if it was him or my crab that is on the surface. So I don't know if I need to do an emergency dig up(which I don't want to do unless necessary) or just leave him be.

It is normal for them to stay still at different stages during the molting process. You can actually see him though? Does it look like there is room for him to move around, like he is inside a cave? I wouldn’t tap the glass or regularly pick the tank up to check, I’d imagine that is causing stress for him and your other crabs.

Because you have had another crab unsuccessfully molt, and you are worried that he might be in danger of the same thing, if you wouldn’t mind filling this part of the ‘help request template’ out, it may help us to see if there might be anything we can recommend , or to get a better idea of what may be going on.

1. What kind of substrate is used in your tank and how deep is it?

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?

3. Is a heat source used in the tank? If so, what?

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)?

5. What kinds of food do you feed and how often is it replaced?

6. How long have you had the crab and what species is it, if known?

7. Has your crab molted, and how long ago did it happen?

8. What type of housing are the crabs kept in, what size is it and what kind of lid is on the housing?

9. How many crabs are in the tank and about how large are they?

I can't see through the crab, but I can see him. It does look like he has a cave and room to move around.

1. The substrate is a coconut fiber/play sand mix and the substrate is 5inches deep where the crab is located. At its highest is 6 inches. The other one has been digging up a storm and moving a lot of the substrate and I suspect he is about to molt again since he has moved into a larger shell.

2. Yes I have a temp/humidity gauge and the humidity is 88 and the temp is 79 degrees. This is about normally what it is.

3. I use the zoo med UTH on the outside sides of the tank.

4. I have a fresh and salt water bowl for them. I mix up their water in 2 separate gallon jugs and treat them with API Tap water conditioner and use instant ocean for the salt water.

5. I give them fresh carrots, omega one freeze dried brine shrimp and honey as a treat. I change out their food/water every 2 days 3 at most.

6. I have had this crab for about 6 months or so and he is a purple pincher

7. Since I have had the crab he has not molted. I believe this is his first molt.

8. They are in a 10 gallon tank with a glass lid

9. There is 2 total in the tank. The crab that is underground is about golf ball size (give or take some) and the other crab (also a purple pincher) is a little smaller than that and have had him for about 8 months.

6 months seems long for his first molt.
The only thing i really question is the food you are offering. Are the carrots organic? If not, carrots end up absorbing a lot of fertilizers and pesticides, and with them being a major part of the crabs' diet, might be making them sick. Also by not offering a wide range of foods, the crabs might not be getting proper nutrients to molt and live healthily. Please refer to the food section for lots of references regarding food. viewtopic.php?t=92554
Also how do you give the crabs water? What size pools, how deep, how often are water changes?


Crabbers unite!!!

The carrots I give them are organic. I've given them coconut, blueberries, walnuts and organic peanut butter before, but carrots have been a major part of their diet in the last few months. Their water is in round dishes. The fresh water is an inch deep, while their salt water dish is about an inch and 1/2 with a few stones to help them get out if they need them. I change these every few days and sometimes twice a day because my other crab feels the need to dig under them and tip the water out or throw dirt in them. I'll take a look at the food guide too, to help find some things they can eat to get more variety in their diet. I guess my next question is how long is too long of no movement in the cave? He has been digging around under ground now for a month trying to find the right spot, but like I said before I haven't heard him squeaking around on the bottom digging tunnels in a few days and he didn't move when I tapped the glass (which I stopped to not stress him out more).

Make sure you cover the window into his cave with cardboard or dark paper so no light gets in.

The exo is shed during molting, so it appears as a limp, dead body just sitting there. The live, soft crab is behind it, peeling away from it and being still so as to harden without deformities.
You should definitely not tap at any underground crab, esp one that could be molting. Like soilentgringa said, cover up any underground visuals. Crabs need darkness to assist molting. I would say a week of absolutely no movement is cause for concern, but there could be movement that you cant see. Just be real sure that the crab hasn't budged. Best thing would be just say a prayer and leave it be.
You should be changing the water out every day. After water is dechlorinated the bacteria easily develops, and you wouldn't want old water getting your crabs sick. Also if the crabs are tossing the water a lot you will want to make sure the sand at the bottom can still hold its shape, or else molting caves can collapse on a helpless soft crabby.
On food i recommend chopping and freezing stuff, so you can offer a wider variety without always having it on hand. I have a gallon ziploc full of random stuff collected for crabs to eat. You can also purchase cheap variety packs of food from the net to use along with stuff you collect yourself, to expand the offerings. I like offering stuff like hardboiled egg, eggshell powder, peanut butter, honey, nuts, seeds, oatmeal, chia seeds, dried cabbage, boiled shrimp tails, coconut flour, peas and carrots, and food from the hermit crab patch and the hermit crab garden. i keep all that stuff in the freezer.


Crabbers unite!!!

Thank you all for answering my questions. YYWW I'll definitely have to try the freezer method on their food and start changing their water more often. I don't think I saw an exo-skeleton but there might be, I can mainly see his BP. I put a thick magazine under the tank too to help make it dark. He's been a strong active crab so far, so hopefully he'll make it through.

Update* I moved the magazine back this morning to see if there was any signs of movement and I can't see his BP, so he must have moved some during the night and I think having the darkness helped . Should I use the bottle technique to isolate him from the possibility of being eaten by the other crab? I know Walmart has those really big soda bottles that are like $1 that would fit around him and his cave, or would it be safest to not disturb the ground around him?

I know it is almost irresistible to keep from looking to check but if you keep letting light in, it might cause him to put off molting. If you have large pools with bubblers then you don't have to do daily water changes, it just depends on how deep your pools are and how dirty they are. I think alot of people do weekly changes in that case. However if you have small dishes you would change water more often, as YYWW said. You do not need to ISO a crab that has dug down to molt normally. They are hard wired to know what to do, just need peace and absolute uninterrupted black darkness to do it. ISO'ing is only for emergencies.

Will do on not letting light in and keeping it nice and dark. I definitely need to look into bubblers because I do eventually want to get them deeper pools.Thank you all again for the helpful information.

soilentgringa wrote:I know it is almost irresistible to keep from looking to check but if you keep letting light in, it might cause him to put off molting. If you have large pools with bubblers then you don't have to do daily water changes, it just depends on how deep your pools are and how dirty they are. I think alot of people do weekly changes in that case. However if you have small dishes you would change water more often, as YYWW said. You do not need to ISO a crab that has dug down to molt normally. They are hard wired to know what to do, just need peace and absolute uninterrupted black darkness to do it. ISO'ing is only for emergencies.

Just FYI weekly water changes (partial) are more for filtered and cycled pools. You can change 2-3 days if you have 1-3 small crabs that aren't using the water often. You should definitely change the water if the dish has been dirtied.


Crabbers unite!!!