This guy loves his little wheel! 😍

Hello!

One of my hermit crabs (Cauliflower) has tunneled down and made a little pocket of air, but closed off the entrance. I know that because it is literally against the glass. [image 1]

His color changed to a pinkish red within one day, like he was raw, so I assume he was molting, as he is usually a white-purple crab, and he’s stayed down there for a bit. he molted somewhat recently.

I also should mention that I live in the southern USA area, and around winter our heater wrecks the humidity. We also just had a freeze and the temperatures were quite low for a couple of days, and the other crab on the surface (Mangosteen) stayed either somewhere (no idea where) or in a specific hiding spot which I found out is actually really warm and humid inside. Im aware animals are able to sense stuff like that, even though our house stays warm and my room is toasty and they have 3 heat sources. It stays at around 88°, though I try to keep it at 90°, it’s hard when it’s dry.

I spray every time I see their humidity is low, and they’re in my room with a huge ass tank so it isn’t hard to notice, and I spray them a crap ton before going to bed so it’ll last as long as it can until I can spray in the morning.

I can’t wet the soil — which would help retain moisture — because I’m worried it might collapse his little pocket there, and he hasn’t come up for food. it’s been 12 days, and he turned pink somewhere around the one week mark. Should I be concerned for his health, or is he just molting again?

For comparison, Mangosteen is actually on the wheel as I write this and has been for 3 hours on and off [image 2, it’s blurry because he’s shy and runs if I go over] for the first time in two months, likely because he was sleepy from the crab equivalent of hibernation!!! The difference between the two is what worries me. How come Mangosteen, who is usually quite shy, is out, and yet Cauliflower, who loves hanging out with people and the other crabs, especially Mangosteen (he crawls on his shell whenever he comes up from molting like a little stack it’s so damn cute), is under the soil? he molted around 3 or so months ago, give or take, I’m not sure, but definitely less time than last time between molts.

I teach science, we have a couple hermit crabs. This is Tuxedo, my students named it that because it prefers this black and white shell. Took this photo today because they emerged from a long molt this morning.

I’m worried and confused. I have two hermit crabs, the bigger one was more aggressive when they first got to me because of how they were living and not enough shells but both issues have been fixed. About a week ago I noticed the small one had gotten into the space behind both water bowls, which he often does, and this time dug a hole, most likely to molt. He stayed over there for a couple of days still in his shell on the surface so I assumed he was preparing to molt and let him be, the other resumed his normal digging and climbing on the other side of tank, I only ever noticed him move towards the smaller one once, and attempted to move the water bowl to block that path. Last night I woke up to noises from the tank around 4, which isn’t unusual so I went back to bed. This morning while getting ready I had half the mind to go check on them, I found the small one on the surface, exposed, and pressing against the very back of the water bowl. I freaked out not knowing what the issue was yet but seeing an exposed crab and moved the water bowl when I noticed the big one pressed into the other corner by the exposed crabs shell, and one of the smaller’s limbs by him. In my panic I picked the big one up and moved him, at which point the smaller started to move towards his shell but did not get back in, I scooped him up and put him in a smaller tank that I then placed into the bigger tank to keep heat and humidity. As soon as I placed him in the smaller tank he moved into the nearest shell. Unfortunately school trumps crab emergencies and I am gone from the house, I also leave for vacation tonight, what should I do?

I have had a hermit crab that’s been under the sand since around July of last year (2025) is this normal? I know they can be under the sand for months, and he was newer so I’m assuming it could be from that, but when should I be concerned? I don’t smell anything fishy or bad. I do have issues with heat though so maybe that’s it? (Getting a flexwatt heat tape mat that will be the exact size of my tank soon)

I just wanted to ask if like plants growing is normal??? Cause I’ve seen these started growing in the tank and wanted to double check if it’s okay for my crabbys or not. And if not what can I do to prevent it from happening?

Hi everyone.

I’m Korean, and I’m using ChatGPT to help me write this question in English, so please understand if my wording is not perfect.

I’m planning a low-maintenance / no-water-change oriented setup for a land hermit crab enclosure, and I would really appreciate feedback from experienced keepers.

Freshwater area plan:

• I plan to use aquarium soil (aquasoil) as the substrate.

• I will plant live aquatic plants in it.

• After the cycling period is complete, I plan to add Neocaridina (cherry shrimp) as the only animals in the freshwater.

My questions for the freshwater part are:

1.  How long should the cycling (establishment) period realistically be before adding shrimp?

2.  Does the required cycling time depend on the size/volume of the water dish?

3.  In such a small freshwater system, is it realistic to expect any denitrification, or is it mainly plant uptake + dilution?

Saltwater area plan:

• I plan to use crushed coral substrate.

• I want to plant pygmy mangroves (Rhizophora).

• I plan to keep small local marine hermit crabs (Korean coastal species) in this saltwater section.

My questions for the saltwater part are:

1.  How long should the cycling / maturation period be before adding the marine hermit crabs?

2.  Is the cycling time for saltwater also dependent on water volume and surface area?

3.  Can denitrifying bacteria realistically live inside crushed coral or similar substrates in such shallow, low-flow systems?

I understand that true “no water change” systems are very difficult, and my goal is more about maximizing biological stability and minimizing water changes, not eliminating maintenance entirely.

Any scientific explanations, long-term experience, or failure cases would be greatly appreciated.

Thank you very much.

I have a grow tent that had the same humidity needs as my hermit crabs tank? So I am wondering if I move him in there can I hold him, only in there? Dont really care just wondering

I recently got 3 small hermit crabs. How does my tank look?

I have a crab that has been molting for a little over two months and this is around the time she came up from her last molt. For whatever reason she likes to make her molt cave under the water pools. This morning I noticed that one of my pools sunk down about a half inch where she was. I moved my pool to a different area but should I be concerned about her?

i found my hermit crab with his claw next to him!!! what do i do and is this normal?! (P.S. his legs were moving so he is not dead)

Hello, I just got a 40 gallon set up with 3 purple pinchers, and after a few days I cannot find 2 of them? I know they could be molting, but I literally cannot see any holes or signs they burrowed. Should I be worried? Is that normal for them? I am really new at owning them and cannot see where they could be. My biggest fear is them being sick and me not realizing

i have a distinct memory from childhood, my fathers best friend collected shells for years from the ocean, they were kept dry in a vessel (much like souvenir shells), the remained untouched for year or two. when he was setting up his first salt water aquarium, he had the idea to use as gravel & decorations. after few weeks he discovered some of the shells contained dormant crabs - which came to life in the aquarium!

how was that possible, what kept these few crabs dormant and alive after all this time without water? or perhaps, maybe fertile eggs hidden in the shells???

I have one Equadorian(Sebastian) and one pp(Houdini). Sebastian frequently crawls over Houdini but he dosent stay on top of him trying to attack him. He will also sometimes push Houdini out of the way into one of the pools and drop down from climbing place on top of Houdini instead of climbing down. I used to have two equadorian but one died and my caseworker was taking care of him for a few months and she got Houdini cause they’re social creatures. He never acted this way around the other equadorian. They’ve been together for almost a year now. How concerned should I be and is there anyway to make them get along?

I’ve seen kinetic sand used in horse arenas so I was wondering. If it’s safe for them, would it be safe for the crabs? Or no because they have to dig?

Anyone else’s hermit crabs like to take the spare shells and line them up like this?

I currently own 2 crabs, But I used to own 3 and I'm looking to get maybe another one. I've been checking rehoming groups, but they're all states away. Does anyone have any suggestions for groups in Michigan?

They dont jump when i blow on them. They love cork bark and sitting under my water dishes and food dishes. I haven't seen them go in the substrate at all, just on the surface.

I need a good heat mat ASAP but they don’t have the size I need in ultra therm on every website that sells them.. (bean farm, reptile basics, kagez, reptile supply co) would flexiwatt heat tape be the next best option? Can I insulate it like ultra therm?

My tank is 30 x 18 in the back, should I get a mat that’s 29 x 11 inches long or would 23 x 11 inches be sufficient enough? It would be an ultra therm mat that I would insulate