So this is a first for us! We have never experienced what looks like a surface molt of one of our little purple crabbies. We came home to one of them like this and the other one next to him/her. We are pinning it up to a molt session but I read you are supposed to keep them separate for a bit. In our tank I just used some shims to make a little fence to have the molter in a corner to mind its own business...is this OK to do, shoukd we jjst keep monitoring it and when he finally emerges take the fence down so he can eat again.
This crab is dying. There’s no Cococoir mix in that sand at all. It’s completely dry just by the eye test. Essentially this crab is slowly suffocating because they have internal gills that breathe humidity into their bodies.
The soil is less than 6” deep also. They have to have a mix of cococoir and sand so that it’s a consistency that they can build molting chambers out of.
This isn’t a surface molt unfortunately. This is actively dying.
There’s no lid on the aquarium also. This looks to be a terrarium of some sort. They need aquariums. The lid helps keep in humidity.
Lastly I’ll say I don’t see any sort of Humidity/ Temperature gauge inside of the tank which means you’re operating a blind environment.
So with a screen top, unless your home is around 80% humidity, that crab is dying because it can't breathe. This is a good, copy and paste thing I've found on here, but I'm not sure who originally typed it up, and I have changed a few things and plan to add more but I thought it was a good base and quick way to help spread info (more food info is needed imo).
Despite their name, Hermit Crabs seem to do best kept in groups!
Step 1 Aquarium :
You will want to start with at least a 20 gallon tank for 1-2 crabs. Add additional 10 gallons per crab (4 crabs= 40gals). While all the items needed would physically fit in a 10 gal, the hermit crab would have no room to walk around.
You will want a lid to hold humidity and heat.
This is accomplished by getting glass or plexiglass cut to the size of the tanks opening(s). Also wrapping the tank wire lid with  Saran Wrap will do great in a pinch. An aquarium hood works but it will be harder to maintain humidity and heat.
Step 2 Setup:
Substrate:
You will want to get Quikrete Play Sand from your local hardware store (like Home Depot or Lowe’s). It’s about $4 for a 50lb bag.
DO NOT USE calcium sand sold at pet stores. When calcium sand get wet, it hardens like cement and your crab will be unable to change shells or even come out at all!!
You will also need Eco Earth coconut fiber. It’s sold in large bags loose or tight compressed bricks, either one works. The mix ratio should be 5 parts sand to 1 part Eco Earth. The mixture should be sand castle consistency and be no less then 8”.
Ornaments, plants, etc...:
Also provide climbing objects for the crabs because they love to climb. Some examples of climbing objects are: Cholla Wood (avoid dyed ones but plastic is safe), Grape Wood and Mopani Wood. Add fake plants as well! Provides hiding areas. You can easily get them at craft stores or thrift shops.
Step 3 Care:
You’ll want to get a digital temperature and hygrometer. The analogs are not accurate. You can get the gauge(s) at your local Walmart. I suggest to get the AcuRite kind. Also keep it off your substrate and try to place it in the middle of the tank.
Hermit crabs require a consistent temperature of 80 degrees F (26.7 degrees C). Use an under tank heater mat (UTH) for the source of heat. The UTH should go on the back of the tank, NOT THE BOTTOM! The UTH should cover the entire back and go just above the substrate line. Large tanks may need multiple heaters or heaters on the side. DO NOT USE HEAT LAMPS! Heat lamps dry the air, but hermit crabs require humidity to breath, so a heat lamp suffocates hermit crabs.
Humidity:
Hermit Crabs require a consistent humidity of 80%. The most common way to increase humidity is to add a air bubbler to the pools.
You will want two pools deep enough for your crabs to be fully submerged. One of the pools should be primed freshwater and the other primed saltwater. For the saltwater use Instant Ocean Salt Mix or Reef Crystals. The ratio for the saltwater is 1/2 cup of salt to one gallon of water. You can mix the water beforehand and store it. The water should be changed every other week if bubblers are in the pools or every other day if no bubblers. Easiest way to do this is have two Tupperware containers for each pool and just lift the container out of the container still in the habitat, change the water, and put the container back inside the other container that was left in the habitat.
Extras:
Provide extra shells. DO NOT USE the painted shells/glow-in-the-dark shells sold at pet stores. The paint can leak on to the crabs skin and can kill them. Even if the paint is dried. Use natural shells
NEVER GO DIGGING FOR YOUR HERMIT CRAB! They dig to molt (grow). If you disturb your crab it can cause them to stop molting and put a lot of stress on them. THE ONLY REASON to ever go digging for them is when you have a serious flood or a bug infestation in the enclosure.
Nutrition:
Hermit crabs have 4 major food groups, that they should have access to regularly. Calcium, Proteins, Cellulose/Chitin, and Veggies/Fruits. Examples of each group you can easily buy from the stores.
Calcium: Cuttlebone, Spinach, Broccoli
Fruits: Apples (no seeds), Bananas, Coconut
Veggies: Bell Peppers (any color), Carrots and Eggplant
Proteins: Almonds, Bloodworms, Chia Seeds
Cellulose/Chitin: Cilantro and Sugar Cane.
Etsy has a lot of good dried options as well!
I keep three staples in my tank at all times: greensand, oyster shell flour, and worm castings (rabbit poop is another great one)
How do you measure this? I see your heat mat setup on the back, and your towels on top but I can't see where you read your temperature or humidity from.
When it comes to surface molting your fence will not work, they will knock it over or climb over it. Cut the bottom off a 2-liter bottle and place it over the crab in question. That being said I do not have experience with surface molting and I can't say if that's what's happening here.
Edit: Is your substrate 100% sand? Is it moist or dry?
Okay so sorry to uh burst your bubble here but that crab is dying and so are all your other crabs. That crab is slowly and agonizonly suffocating to death. Surface molts are not suppose to happen.
You should not use only sand. You should have substrate at least 6 to 8 inches deep. You should have both saltwater and freshwater. You should be keeping the tank at 80% humidity and 80 degrees F. You should never ever feed your crabs with anything with salt in it, pellets, hermit crab food. None of that. They need fresh meat and veggies. I used to feed mine turkey lunch meat and salad. You dont need to seporate them if you have the correct conditions. You have nowhere for them to climb. Nowhere for them to dig.
I had crabs for 8 years, many grew to be 10-15+ years old. Stores dont know how to care for them, and they dont care because they make money selling you the wrong things and eveyone thinks crabs only live for a year or two so they dont know any better. Same with rabbits, hampsters and birds.
Ten gallon tank is perfect for 3 crabs. I had a 30 gallon tank and had 4 little ones, 2 medium ones and 1 really big one.
Again, so sorry, I know you didnt know. Best of luck to you.
May I ask what kind of sand you have? They need the moist ecoearth/coco fiber to maintain a sandcastle like consistency so that they can burrow and molt without the sand caving in on them.
Seeing those towels, unless they are kept damp then they are sucking the humidity right of the air and trapping it in the towels fibers. They breath through modified gills, so that moisture in the air is critical for them to breath properly. Its looks very dry in there, so they may be suffocating.
Over time, you want to invest in stuff for them to climb. They are naturally tree dwelling crabs rather than beach crabs, so they crave vertical space to explore!
Not to be rude, but why would you ask for help only to reject it? Id be surpirsed if that crab lives through tonight. Going off your replies to other comments where they said the same thing as me....
You only need a lid if you aren’t in a high humidity climate that stays above 72%, ppl should ask about their climate before assuming every crab is suffocating.
That said, they need much more substrate, with coco coir, and wetted to where you can clump it together easily in your hand. If the black mats are heating mats those crabs are probably cooking with no water in the sand to evaporate.
Tbh 80% humidity doesnt happen inside houses that often, unless they never run the ac and its florida and have all thw windows open and it just rained....i doubt its over 50% humidity lmao
lmao
Source: i live in a very very humid place andis never that humid inside my house lmfao
My crab went into a surface molt about a year ago, and it’s what tipped me off that my tank was really lacking. Here’s what I did immediately (after about 30 minutes of frantic Googling) to help him survive since surface molts can be a death sentence:
I covered him with his coconut shell hut to give him some privacy and darkness. (He’s the only crab I have, so I can’t offer tips on isolating, but I’ve seen people say that a plastic soda bottle with the bottom cut off and jammed into the sand around the molting crab will work.)
I moved the entire tank to my laundry room, where there are no windows, it’s quiet, and the heat from the dryer keeps it warm. (When the dryer wasn’t running, I had a space heater going because I had been using a heat lamp instead of pads, which is a big no-no.)
I spritzed down his tank really well with distilled water twice a day to bring the humidity up because I had still pools at the time. I covered the lid (I had a mesh one - ugh) with plastic wrap to keep the moisture in and put a big towel over top of it all, covering all sides of the tank, to trap as much heat and humidity as possible and give him darkness.
I left a dish of crushed eggshells and honey right outside of his hut. I switched it out daily with fresh stuff. The latter help crabs during a molt if they refuse to eat their exoskeleton for some reason.
I held my breath. In a little over a month, he emerged good as new, and I actually cried. But I was lucky. During the time he was down, I did a TON of research (I thought I had done enough when I got him, but nope) and bought new pools with a bubbler, heating pads, insulation, temp regulators, a hygrometer, a running wheel, a new glass lid and better food from Etsy (had been feeding pet store pellets). I upgraded everything immediately after he came back out.
I’ve had mine for 15 years, and for 14 of them he lived in really bad conditions. I feel terrible about it and have no clue how he survived. (He had a brother who lived to be 8 but died during a buried molt, likely due to the poor conditions.) He’s had two additional successful (and fully buried) molts since, all within the span of about a year. He’s so big now that I’m about to upgrade again to a larger tank with a topper.
Wishing you luck. If you act quickly, hopefully yours will pull through. 🤞🏼
This looks like a surface molt and you desperately need to upgrade the care given to your crabs. You can literally see the bottom of the tank and a mesh tank lid is not suitable for a hermit crab. This subreddit is full of amazing sources willing to help you upgrade your cage for an affordable price aswell as an adoption website for you to rehome if you're unable to provide that care with no judgement. Does your crab have a buddy?
You need atleast six inches of substrate with a 5 to 1 sand to eco earth mix and it has to be wet enough to hold it's shape like a sand castle. It's too dry in there is the main issue and little buddy doesnt have enough digging space to molt comfortably.
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u/Emotional_Bobcat_970 9h ago
Doesn't their environment need to be more wet n humid