HCA: Hermit Crab Association

Since you've come to the emergency forum, we know you want a fast answer to your question. In order for us to figure out the problem as quickly as possible, we ask that you answer the following questions as best you can. Some of them may seem odd, but they're all designed to give us the information we need to give you a good solution for your problem. The things in the [ brackets ] are there to make this post easier to read once submitted. Thanks!

I wasn't sure if this constituted an emergency or not, but I kinda need info sooner rather than later to ensure my crab survives!


1. What kind of substrate is used in your tank and how deep is it?
7-8 inches of ecoearth/playsand.


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?
I have 2 hygrometers set at roughly each third of the tank, one thermometer besides one hygrometer, and I use a thermometer/controller with the probe taking the reading from the center of the tank.


3. Is a heat source used in the tank? If so, what?
I use a 3x20 heat pad controlled by a thermometer to stop at 83 degrees.

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)?
Both types, treated with Prime, salt was originally Thrive brand salt but I've recently got some Instant Ocean and I'm gonna start using that soon. Both pools have bubblers too.

5. What kinds of food do you feed and how often is it replaced?
I feed them chia seeds, flax seeds, dried coconut, dried pineapple, mealworms and earthworm castings. All organic. Taken out during the day, put back in during the night.

6. How long have you had the crab and what species is it, if known?
I've had him since I think the first week of December? And he's a purple pincher.

7. Has your crab molted, and how long ago did it happen?
This is the first time, last time I saw him was December 24th.

8. What type of housing are the crabs kept in, what size is it and what kind of lid is on the housing?
I keep him in a 50 gallon plastic tote, 39.75" long, 21.5" wide, 17.88" tall.

9. How many crabs are in the tank and about how large are they?
3, the one I'm referring to and a different one are roughly quarter-sized, one is a little bigger but he's just come up from his own molt and I haven't really been able to get a good sizing on him.

10. How many extra shells are usually kept in the tank, if any?
Don't remember off the top of my head, but a good amount.

11. Have there been any fumes or chemicals near the crabitat recently?
None that I know of.

12. How often do you clean the tank and how?
I give the sides a wipe down every day, that's about it.

13. Are sponges used in the water dish? If so, how are they cleaned?
None.

14. Has anything new been added to your crabitat recently?
A lot of things - new water dishes, moss, one of those spinning saucers, etc. A lot was added after this one went down for his molt so I'm not sure. There's been chia growing since before he went down too.

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.)?
Everything else will probably be addressed in the next point.

16. Please describe the emergency situation in detail.
So my shell shop is a little tupperware filled with sphagnum moss and with shells on top. This crab, who I've had for a while now and am dead set on keeping alive, decided that instead of molting in the lovely 7-8 inches of substrate in the rest of the tank that one of his tankmates molted in, he would molt INSIDE THE SHELL SHOP. Rather annoyed at that little turd.

I didn't know until 2 days ago when I was about to swap out the design and change it from being filled with moss to having it covered with cocofiber liner. He's went the entire molt period inside the moss of the shell shop. Like I said, he's been gone since December 24th and he looks about done. His exoskeleton is laying just next to him, and he's responsive to very light touches with a bit of moss.

I've put a lid over the tupperware with holes cut into it and I'm monitoring him. He's definitely moved since I've found him - his shell is now facing the exoskeleton - but I'm really concerned with letting him out at the correct time so his tankmates don't eat him, but I don't want to keep disturbing him. I also don't want him doing the exact same thing again!

Is this normal for a crab to do? This was my second molt ever and I'm really annoyed at the little troublemaker for picking there of all places to molt in. It's a miracle that his tankmates didn't find him before I did considering how long it's been and that they would've picked up on the molt scent. What should my steps moving forward be to ensure he stays alive during this period?

For picture references:

Here's what the shell shop looked like when I first discovered him in there:

https://i.imgur.com/KyNk3fk.jpg

Here's him in there: (could someone let me know how close he looks to being finished too?)

https://i.imgur.com/dAPu5rK.jpg

Here's him as of tonight, having moved the opening of his shell to face the exoskeleton:

https://i.imgur.com/9wR5F3j.jpg

1. What kind of substrate is used in your tank and how deep is it?
7-8 inches of ecoearth/playsand.


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?
I have 2 hygrometers set at roughly each third of the tank, one thermometer besides one hygrometer, and I use a thermometer/controller with the probe taking the reading from the center of the tank.
Curly - What are your readings?

3. Is a heat source used in the tank? If so, what?
I use a 3x20 heat pad controlled by a thermometer to stop at 83 degrees.
Curly - Is it on the back?

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)?
Both types, treated with Prime, salt was originally Thrive brand salt but I've recently got some Instant Ocean and I'm gonna start using that soon. Both pools have bubblers too.

5. What kinds of food do you feed and how often is it replaced?
I feed them chia seeds, flax seeds, dried coconut, dried pineapple, mealworms and earthworm castings. All organic. Taken out during the day, put back in during the night.
Curly - If all this is dried, you can leave it in for a few day before changing it out. I generally leave dried food until I see it's getting fuzzy mold on it LOL.

6. How long have you had the crab and what species is it, if known?
I've had him since I think the first week of December? And he's a purple pincher.

7. Has your crab molted, and how long ago did it happen?
This is the first time, last time I saw him was December 24th.

8. What type of housing are the crabs kept in, what size is it and what kind of lid is on the housing?
I keep him in a 50 gallon plastic tote, 39.75" long, 21.5" wide, 17.88" tall.

9. How many crabs are in the tank and about how large are they?
3, the one I'm referring to and a different one are roughly quarter-sized, one is a little bigger but he's just come up from his own molt and I haven't really been able to get a good sizing on him.

10. How many extra shells are usually kept in the tank, if any?
Don't remember off the top of my head, but a good amount.

11. Have there been any fumes or chemicals near the crabitat recently?
None that I know of.

12. How often do you clean the tank and how?
I give the sides a wipe down every day, that's about it.

13. Are sponges used in the water dish? If so, how are they cleaned?
None.

14. Has anything new been added to your crabitat recently?
A lot of things - new water dishes, moss, one of those spinning saucers, etc. A lot was added after this one went down for his molt so I'm not sure. There's been chia growing since before he went down too.

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.)?
Everything else will probably be addressed in the next point.

16. Please describe the emergency situation in detail.
So my shell shop is a little tupperware filled with sphagnum moss and with shells on top. This crab, who I've had for a while now and am dead set on keeping alive, decided that instead of molting in the lovely 7-8 inches of substrate in the rest of the tank that one of his tankmates molted in, he would molt INSIDE THE SHELL SHOP. Rather annoyed at that little turd.

I didn't know until 2 days ago when I was about to swap out the design and change it from being filled with moss to having it covered with cocofiber liner. He's went the entire molt period inside the moss of the shell shop. Like I said, he's been gone since December 24th and he looks about done. His exoskeleton is laying just next to him, and he's responsive to very light touches with a bit of moss.

I've put a lid over the tupperware with holes cut into it and I'm monitoring him. He's definitely moved since I've found him - his shell is now facing the exoskeleton - but I'm really concerned with letting him out at the correct time so his tankmates don't eat him, but I don't want to keep disturbing him. I also don't want him doing the exact same thing again!

Is this normal for a crab to do? This was my second molt ever and I'm really annoyed at the little troublemaker for picking there of all places to molt in. It's a miracle that his tankmates didn't find him before I did considering how long it's been and that they would've picked up on the molt scent. What should my steps moving forward be to ensure he stays alive during this period?

Curly - You did the right thing by putting a vented lid over the container! This way, he is safe from the other crabs, but still in the same good tank conditions. He will need to eat his exoskeleton (or most of it at least), while his new exo hardens. The actual shedding of old exo doesn't take long, it's the eating and hardening that takes a while. You will want to leave him in isolation until you see him moving around normally, which could be a couple of weeks. I would avoid touching him for a while still. And then you might give him some other foods in there, and a bottle cap of water, before letting him out. And when you do let him out, consider giving him a quick dip in the fresh water so that the 'molt smell' is washed off (it would usually be 'scrubbed off' when they dig back up through the sub.

I've had this happen before with small crabs, it's like they know they can pull a quickie safely in either the shell shop or the moss pit and they just go for it. Usually it's super fast molts, where they're done in 5 days or less. They should finish up 90%+ of their shed exo and be up and moving around normally when they're finished. I panicked the first few times it happened - isolated, observed, was totally nerval about it. And then when a couple of the same small crabs kept doing it monthly it was sort of like, you do you dude, and I started leaving them and it was never an issue even when other crabs were hanging out right next to them.

That said, you've got a brand new crab to your tank. There is a strong possibility that what you're seeing this time is a symptom of post purchase syndrome where an "easy" molt is taking less energy to pull off. I think isolating him for safety is the right course of action. Wait until he's exploring and eating and drinking normally before letting him around other crabs just in case. Then see what happens in the future and know to keep an eye out if he suddenly disappears again, at the size of a quarter it could be time again in as little as 4 to 8 weeks.

curlysister wrote: ↑

Wed Jan 10, 2024 12:06 am

Curly - What are your readings?

Temperature annoyingly seems to vary quite a bit - I've had times where I come home and it's a balmy 82° and it'll maintain that throughout the night and into the day, and sometimes I'll come home and it'll be 78°ish. I just last night had a scare where I came home to it at 76°. I've got shower towels or whatever they're called on top, and due to last night I've put a polar blanket over the top (nothing covering heat pad ofc!) I've also got a far larger ReptileBasics UTH ordered as of yesterday because of that little scare, and to prepare for the summer.

The humidity is far more stable, I've not seen it dip below 80% in a long time unless I have the lid open for an extended period. It's almost always at a stable 89%.

curlysister wrote: ↑

Wed Jan 10, 2024 12:06 am

Curly - Is it on the back?

Yep! It's not the best coverage as it's only a 3x20, but like I said I've got a bigger, beefier, better one coming.

curlysister wrote: ↑

Wed Jan 10, 2024 12:06 am

Curly - If all this is dried, you can leave it in for a few day before changing it out. I generally leave dried food until I see it's getting fuzzy mold on it LOL.

My boys are all messy eaters and will leave food tipped out of the dish on the substrate where I don't see it and mold will grow, and while they aren't voracious eaters, organic dried pineapple and their favourite organic dried coconut ain't cheap!

curlysister wrote: ↑

Wed Jan 10, 2024 12:06 am

Curly - You did the right thing by putting a vented lid over the container! This way, he is safe from the other crabs, but still in the same good tank conditions. He will need to eat his exoskeleton (or most of it at least), while his new exo hardens. The actual shedding of old exo doesn't take long, it's the eating and hardening that takes a while. You will want to leave him in isolation until you see him moving around normally, which could be a couple of weeks. I would avoid touching him for a while still. And then you might give him some other foods in there, and a bottle cap of water, before letting him out. And when you do let him out, consider giving him a quick dip in the fresh water so that the 'molt smell' is washed off (it would usually be 'scrubbed off' when they dig back up through the sub.

Haven't touched him since! Dropped a bit of coconut in next to him last night, but as of tonight, just getting home, he hasn't shown any interest. He's been munching on his exoskeleton, caught him last night wiggling his leg towards it, so at least he's showing some activity. He's visibly moved too and his shell is now facing downwards rather than towards the exoskeleton.

What's a good indicator that he's done hardening and is ready to come out of his prison sentence for picking the worst possible place? A part of me would assume that it'd be him moving around, but I'm gone literally 11-12 hours of the day usually, and there's no guarantee that he'd be active and making a show of wanting to get out while I'm home.

wodesorel wrote: ↑

Wed Jan 10, 2024 12:38 am

I've had this happen before with small crabs, it's like they know they can pull a quickie safely in either the shell shop or the moss pit and they just go for it. Usually it's super fast molts, where they're done in 5 days or less. They should finish up 90%+ of their shed exo and be up and moving around normally when they're finished. I panicked the first few times it happened - isolated, observed, was totally nerval about it. And then when a couple of the same small crabs kept doing it monthly it was sort of like, you do you dude, and I started leaving them and it was never an issue even when other crabs were hanging out right next to them.

That said, you've got a brand new crab to your tank. There is a strong possibility that what you're seeing this time is a symptom of post purchase syndrome where an "easy" molt is taking less energy to pull off. I think isolating him for safety is the right course of action. Wait until he's exploring and eating and drinking normally before letting him around other crabs just in case. Then see what happens in the future and know to keep an eye out if he suddenly disappears again, at the size of a quarter it could be time again in as little as 4 to 8 weeks.

So here's the thing - his last sighting before disappearing for a molt was December 24th. Makes sense that he'd be finishing up right around now (although a larger crab of mine I think finished their molt before he did?), but the timeline gets trickier when it expands.

He (the shell shop molter) is actually the crab I've had the longest. The family got him and a different one the first week of December as part of some school thing for my little brother. Being a 9 year old he naturally lost interest quickly, and I ended up adopting them. Sadly, that different one died of presumably PPS before I took things over.

A few days after I took charge of the shell shop molter, I got the 50 gallon plastic tote he's living in now and set everything up. A week after that, I got him 2 tankmates - one is just a tiny bit smaller and still hasn't molted, the other is larger than both and has recently reappeared after what I assume was a molt (he was MIA since December 22nd).

He's been in my care for the longest, so I don't think it's PPS. He's had a good month of proper living conditions by now. But I'm not exactly an expert on crabs - for all I know they could suffer from PPS for months after finally moving in to better conditions!

I don't really have any good way to isolate him at the moment - I do still have the smaller, crappier tank that my family originally got, but it's got calcium sand in it and I'm all out of real estate in my room to place the isolation tank, as well as heating sources, etc. Like I asked curly - what's a good sign that he's ready to come out of prison and rejoin his civilized crab society?

And as far as keeping an eye out if he suddenly disappears again - the moment he's ready to rejoin the others, I'm swapping the current shell shop plan where it's shells and sphagnum moss to a cocofiber lined pit with shells in it. That was my original plan, but I DEFINITELY don't want to catch him or another crab molting in a silly place like that again!

Crabs are susceptible to PPS until after at least their first molt in good conditions. Like Wode said, he could have opted for the shell shop because it would take less energy than digging down into the sub.
Isolating him in the container he is in now with holes in the lid is perfect! No need to put him in a separate tank.