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!


1. What kind of substrate is used in your tank and how deep is it?
3-4 inches of Sand and Soil mix from petsmart.

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 I do. The humidity is usually between 90-99 and it's heat recently has been between 60-85 because of heating problems
3. Is a heat source used in the tank? If so, what?
Heat pad on the back of the tank.

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 fresh and salt is available. Standard dechlorinator and sea salt mix is used (about 2 very small scoops)

5. What kinds of food do you feed and how often is it replaced?
Mealworms, egg yolk, egg shell, honey when given proper diet. mealworms when they are all underground, food is replaced every 12-24 hours.

6. How long have you had the crab and what species is it, if known?
Dark crab- 4 months, white crabs- 3 months, same species but I don't know the name

7. Has your crab molted, and how long ago did it happen?
No molting that I know of has occurred

8. What type of housing are the crabs kept in, what size is it and what kind of lid is on the housing?
20 gallon fish tank (Length- 20 inches, Width-10 inches, Height- 12 inches) the lid is a glass foldable lid so I can open it with ease while keeping heat and humidity in.

9. How many crabs are in the tank and about how large are they?
3 crabs, A large dark crab, a medium sized white-brownish crab and a little white-brownish crab

10. How many extra shells are usually kept in the tank, if any?
10 shells (plus the 40 that I have in a separate container next to the tank)

11. Have there been any fumes or chemicals near the crabitat recently?
No. I make sure to keep any chemicals away from the cage and crabitat at all times.

12. How often do you clean the tank and how?
I clean the tank when it starts to get any slightest bit nasty or moldy with the paper towels and cleaning wipes.

13. Are sponges used in the water dish? If so, how are they cleaned?
No sponges, I have bowls for there salt and fresh water needs and it seems to me from what I can see is that they clean themselves.

14. Has anything new been added to your crabitat recently?
Besides the daily mealworms that I feed them as a snack just in case they come out from burrowing, No.

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.)?
I mist there cage regularly and I put mealworms in there on a daily basis.

16. Please describe the emergency situation in detail.
I own three Hermit Crabs that I bought at different times in Hampton Beach, I bought them both this summer. I have a darker crab (Big crab) and two white crabs (One medium sized one and one really small one). I bought the white crabs at the end of summer and the darker one at the beginning of summer. I have them in a 20 gallon tank (20 length, 10 width, 12 height) with about 3-4 inches of sand and soil mix, its at a sand castle consistency and it holds their caves up nicely. As for decoration I have rock stairs that they climb on and hide behind and a fake wooden trunk with natural shells in it. There are some real and natural gastropod shells in there as well as scalop shells for decor. They have a fresh water and salt water bath as well as a bowl for food. I put some dead mealworms in there as of right now because of certain reasons which Ill get into when I explain the problem I'm having. The dark crab and the little crab have changed shells from their nasty painted ones but the medium sized one hasn't yet. Now for the issues I'm having. The heating pad on the side of the tank isn't producing enough heat for them so I've had to start using a heating blanket to put on top to keep them warm. I've had the dark big crab for 4 months and he was underground for a month and half. About a month after I bought him I bought the two white crabs and put them all in the same tank, I don't know if they know that the other crabs in the tank exist cause I never see them which leads to my next concern. Now I've been on here before so when I found out that they go underground to molt or acclimate to their surroundings I wasn't to concerned but now I'm starting to get really concerned for the reason that it's been 3 months and I rarely see them come up. I've only been putting some mealworms in there so that way I'm not wasting all my moms food if they don't eat it (I'm 15 and I live with my single mother, my little brother and my four other animals) and I know that's not a balanced diet but I will start balancing their diet once I get this all figured out. They are underground all the time and they never molt or come up to eat or drink. I'm really getting worried for them cause I want my crabs to be happy in there home but they can't if they seem scared and don't trust me (all three of them are afraid of me) please it's very clear that I need a lot of help with these guys and any info would be great! Thamkyou to everyone in advance.

I own three Hermit Crabs that I bought at different times in Hampton Beach, I bought them both this summer. I have a darker crab (Big crab) and two white crabs (One medium sized one and one really small one). I bought the white crabs at the end of summer and the darker one at the beginning of summer. I have them in a 20 gallon tank (20 length, 10 width, 12 height) with about 3-4 inches of sand and soil mix, its at a sand castle consistency and it holds their caves up nicely. As for decoration I have rock stairs that they climb on and hide behind and a fake wooden trunk with natural shells in it. There are some real and natural gastropod shells in there as well as scalop shells for decor. They have a fresh water and salt water bath as well as a bowl for food. I put some dead mealworms in there as of right now because of certain reasons which Ill get into when I explain the problem I'm having. The dark crab and the little crab have changed shells from their nasty painted ones but the medium sized one hasn't yet. Now for the issues I'm having. The heating pad on the side of the tank isn't producing enough heat for them so I've had to start using a heating blanket to put on top to keep them warm. I've had the dark big crab for 4 months and he was underground for a month and half. About a month after I bought him I bought the two white crabs and put them all in the same tank, I don't know if they know that the other crabs in the tank exist cause I never see them which leads to my next concern. Now I've been on here before so when I found out that they go underground to molt or acclimate to their surroundings I wasn't to concerned but now I'm starting to get really concerned for the reason that it's been 3 months and I rarely see them come up. I've only been putting some mealworms in there so that way I'm not wasting all my moms food if they don't eat it (I'm 15 and I live with my single mother, my little brother and my four other animals) and I know that's not a balanced diet but I will start balancing their diet once I get this all figured out. They are underground all the time and they never molt or come up to eat or drink. I'm really getting worried for them cause I want my crabs to be happy in there home but they can't if they seem scared and don't trust me (all three of them are afraid of me) please it's very clear that I need a lot of help with these guys and any info would be great! Thankyou to everyone in advance.

crabs aren't exactly trusting pets to handle and see all the time, theyre also nocturnal which means theyre only really active at night and any light in their habitat will stress them out, id say they need about 3 more inches of substrate as well. perhaps its too bright where youre keeping them? hope this helps! they also need veggies for a balanced diet, try putting some dark leafy greens around the habitat for foraging options! carrots and bell peopers are good for them too

1. What kind of substrate is used in your tank and how deep is it?
3-4 inches of Sand and Soil mix from petsmart.
Curly - Substrate should be at least 2 to 3 times as deep as your largest crab, and needs to be moistened with dechlorinated water so that it is 'sand castle' consistency (holds it's shape but not so wet that water pools in the bottom). What brand/ type is the 'sand and soil mix'? There is some substrate sold at pet stores that is safe, but some that is not.

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 I do. The humidity is usually between 90-99 and it's heat recently has been between 60-85 because of heating problems
3. Is a heat source used in the tank? If so, what?
Heat pad on the back of the tank.
Curly - Do you know that brand of UTH?

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 fresh and salt is available. Standard dechlorinator and sea salt mix is used (about 2 very small scoops)
Curly - What brand is the dechlorinator? And is the salt 'sea salt' or 'marine salt'? What brand is it?

5. What kinds of food do you feed and how often is it replaced?
Mealworms, egg yolk, egg shell, honey when given proper diet. mealworms when they are all underground, food is replaced every 12-24 hours.
Curly - Crabs need a varied diet, which includes protein and calcium daily. Be sure to check out the 'nutrition' care sheet, it has all the info that you will need.

6. How long have you had the crab and what species is it, if known?
Dark crab- 4 months, white crabs- 3 months, same species but I don't know the name

7. Has your crab molted, and how long ago did it happen?
No molting that I know of has occurred

8. What type of housing are the crabs kept in, what size is it and what kind of lid is on the housing?
20 gallon fish tank (Length- 20 inches, Width-10 inches, Height- 12 inches) the lid is a glass foldable lid so I can open it with ease while keeping heat and humidity in.

9. How many crabs are in the tank and about how large are they?
3 crabs, A large dark crab, a medium sized white-brownish crab and a little white-brownish crab

10. How many extra shells are usually kept in the tank, if any?
10 shells (plus the 40 that I have in a separate container next to the tank)

11. Have there been any fumes or chemicals near the crabitat recently?
No. I make sure to keep any chemicals away from the cage and crabitat at all times.

12. How often do you clean the tank and how?
I clean the tank when it starts to get any slightest bit nasty or moldy with the paper towels and cleaning wipes.

13. Are sponges used in the water dish? If so, how are they cleaned?
No sponges, I have bowls for there salt and fresh water needs and it seems to me from what I can see is that they clean themselves.

14. Has anything new been added to your crabitat recently?
Besides the daily mealworms that I feed them as a snack just in case they come out from burrowing, No.

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.)?
I mist there cage regularly and I put mealworms in there on a daily basis.
Curly - You will need to be careful that you don't add so much water with the misting, that you cause a flood. If your huidity is over 75%, you don't need to mist.

16. Please describe the emergency situation in detail.
I own three Hermit Crabs that I bought at different times in Hampton Beach, I bought them both this summer. I have a darker crab (Big crab) and two white crabs (One medium sized one and one really small one). I bought the white crabs at the end of summer and the darker one at the beginning of summer. I have them in a 20 gallon tank (20 length, 10 width, 12 height) with about 3-4 inches of sand and soil mix, its at a sand castle consistency and it holds their caves up nicely. As for decoration I have rock stairs that they climb on and hide behind and a fake wooden trunk with natural shells in it. There are some real and natural gastropod shells in there as well as scalop shells for decor. They have a fresh water and salt water bath as well as a bowl for food. I put some dead mealworms in there as of right now because of certain reasons which Ill get into when I explain the problem I'm having. The dark crab and the little crab have changed shells from their nasty painted ones but the medium sized one hasn't yet. Now for the issues I'm having. The heating pad on the side of the tank isn't producing enough heat for them so I've had to start using a heating blanket to put on top to keep them warm. I've had the dark big crab for 4 months and he was underground for a month and half. About a month after I bought him I bought the two white crabs and put them all in the same tank, I don't know if they know that the other crabs in the tank exist cause I never see them which leads to my next concern. Now I've been on here before so when I found out that they go underground to molt or acclimate to their surroundings I wasn't to concerned but now I'm starting to get really concerned for the reason that it's been 3 months and I rarely see them come up. I've only been putting some mealworms in there so that way I'm not wasting all my moms food if they don't eat it (I'm 15 and I live with my single mother, my little brother and my four other animals) and I know that's not a balanced diet but I will start balancing their diet once I get this all figured out. They are underground all the time and they never molt or come up to eat or drink. I'm really getting worried for them cause I want my crabs to be happy in there home but they can't if they seem scared and don't trust me (all three of them are afraid of me) please it's very clear that I need a lot of help with these guys and any info would be great! Thamkyou to everyone in advance.
Curly - Have you *never* seen them, or *rarely* seen them above ground? If they are coming up and down, there is nothing to worry about. If they are staying under for extended periods of time (or even shorter periods if they are small crabs), they might be molting. When a crab is underground, it does not need to have any food or water. They know what they are doing down there LOL.
While some people do handle their crabs, many of us don't. Because we are big and they are small, they see us as predators. It can take a lot of time and patience until they allow handling.

I think if you can get the heating issues figured out it will help with activity levels. If it's dropping that low it's going to cause them to bury to try and conserve energy and stay warm enough, and anything in the 60s is danger zone in terms of survival. A good quality UTH thay is big enough is really key to getting things toasty, and if it's dropping into the 60s then the room they are in is also cold which is a challenge to heat against. Immediate things to try is to find the warmest area in the house, away from windows and drafts, against an inner wall as it'll be warmer.

You also only have a 10 gallon with those dimensions. They may be a little crowded if your sizing of the crabs is correct.


Not sure what you're currently using for heat, but from personal experience with a 10 gallon in a cold (down to 50s) room, a Flukers 11x11 UTH will do the job. Insulate overtop of it and the lid with foil wrapped cardboard to hold in the heat. Not all brands of UTH can be insulated safely, but Ultratherm and Flukers can, and Flukers can be found in stores like Pecto. (If you have a petco clearance nearby, I got mine for $15!)