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?


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?


10. How many extra shells are usually kept in the tank, if any?


11. Have there been any fumes or chemicals near the crabitat recently?


12. How often do you clean the tank and how?


13. Are sponges used in the water dish? If so, how are they cleaned?


14. Has anything new been added to your crabitat recently?


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.)?


16. Please describe the emergency situation in detail.


I have a 40 gallon tank. 6-8 inches of substrate (play sand and eco earth coconut substrate). Fresh and salt water dishes (they are shallow because my crabs refuse to use anything deeper) using flukers salt and freshwater conditioners. I feed them all organic dried food (crab hub on Etsy) with each meal including calcium, protein, fruits and veggies. Both food and water are changed every other day. Temperature stays at 70-80 via heating pad on back of tank and humidity stays at 70-85. I also have a non heat lamp to simulate day light. I also have multiple shells for each crab. I had 5 S/M purple pincher crabs until the end of December. Then I took in a friends purple pincher crab because his tank mate died and he wanted to re home. About a month later, that crab passed. Then, every few weeks since my crabs started passing. Another crab passed today, leaving me with 2 crabs. We did deep clean the tank after two crabs passed. Also, after each passing, we got rid of the substrate in the area around the crab. I’m looking for some help on WHY they keep passing. I’m trying my best to take care of them and I don’t understand it.

1. What kind of substrate is used in your tank and how deep is it?
6-8 inches of substrate (play sand and eco earth coconut substrate).
Curly - Is it moistened with dechlorinated water so that it holds it's shape?

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?
Temperature stays at 70-80 via heating pad on back of tank and humidity stays at 70-85. I also have a non heat lamp to simulate day light.
Curly - Where are you measuring the heat and humidity (like how close to the heat, or in the middle of the tank, at ground level or part way up, etc)? 70 is a bit low for both heat and humidity.

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)?
Fresh and salt water dishes (they are shallow because my crabs refuse to use anything deeper) using flukers salt and freshwater conditioners.
Curly - Fluker's salt and water conditioner won't remove everything that needs to be, and the salt won't provide all the minerals needed for long term health. Be sure to check out the 'water' care sheet for all the info you need about water.

5. What kinds of food do you feed and how often is it replaced?
I feed them all organic dried food (crab hub on Etsy) with each meal including calcium, protein, fruits and veggies. Both food and water are changed every other day.

6. How long have you had the crab and what species is it, if known?
Curly - How long had you had your crabs? Where did you get the original 5? How long had your friend had their crabs?

7. Has your crab molted, and how long ago did it happen?
Curly - Have your crabs molted with you? Had your friend's crab molted with them?

8. What type of housing are the crabs kept in, what size is it and what kind of lid is on the housing?
I have a 40 gallon tank.
Curly - What do you have for a lid?

9. How many crabs are in the tank and about how large are they?
I had 5 S/M purple pincher crabs until the end of December. Then I took in a friends purple pincher crab because his tank mate died and he wanted to re home. About a month later, that crab passed. Then, every few weeks since my crabs started passing. Another crab passed today, leaving me with 2 crabs.
Curly - What were the circumstances around their deaths? Were they on the surface or buried? Were they in a shell or out? Where were they located when you found them deceased?

10. How many extra shells are usually kept in the tank, if any?
I also have multiple shells for each crab
Curly - HCA recommends 3 to 5 extra shells per crab. Did your crabs change shells while they were alive?

11. Have there been any fumes or chemicals near the crabitat recently?


12. How often do you clean the tank and how?
We did deep clean the tank after two crabs passed. Also, after each passing, we got rid of the substrate in the area around the crab.

13. Are sponges used in the water dish? If so, how are they cleaned?


14. Has anything new been added to your crabitat recently?


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.)?


16. Please describe the emergency situation in detail.

I’m looking for some help on WHY they keep passing. I’m trying my best to take care of them and I don’t understand it.
Curly - I posted a few more questions above (and pasted your answers into the appropriate sections) to try to get more info about your situation.

1. What kind of substrate is used in your tank and how deep is it?
6-8 inches of substrate (play sand and eco earth coconut substrate).
Curly - Is it moistened with dechlorinated water so that it holds it's shape?

-yes I spray it twice daily with dechlorinated water

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?
Temperature stays at 70-80 via heating pad on back of tank and humidity stays at 70-85. I also have a non heat lamp to simulate day light.
Curly - Where are you measuring the heat and humidity (like how close to the heat, or in the middle of the tank, at ground level or part way up, etc)? 70 is a bit low for both heat and humidity.

—the guage is located on the top right corner of the tank (on the back side)

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

—heating pad on back of 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)?
Fresh and salt water dishes (they are shallow because my crabs refuse to use anything deeper) using flukers salt and freshwater conditioners.
Curly - Fluker's salt and water conditioner won't remove everything that needs to be, and the salt won't provide all the minerals needed for long term health. Be sure to check out the 'water' care sheet for all the info you need about water.

5. What kinds of food do you feed and how often is it replaced?
I feed them all organic dried food (crab hub on Etsy) with each meal including calcium, protein, fruits and veggies. Both food and water are changed every other day.

6. How long have you had the crab and what species is it, if known?
Curly - How long had you had your crabs? Where did you get the original 5? How long had your friend had their crabs?

—I’ve gotten each crab at a different time from pet store. One of the remaining crabs is the first crab I got (May 10th 2022). My friend had his crab for 2 years before giving him to me. His tank mate my friend had died 2 months prior to giving his other crab to me.

7. Has your crab molted, and how long ago did it happen?
Curly - Have your crabs molted with you? Had your friend's crab molted with them?

—the original crab that’s still alive molted June 2022. Unsure of my friends crab molted but I’m guessing so due to him owning the crab for 2 years.

8. What type of housing are the crabs kept in, what size is it and what kind of lid is on the housing?
I have a 40 gallon tank.
Curly - What do you have for a lid?

—I have a screen lid with 95% of it wrapped in plastic wrap to keep in humidity. I also have a towel on it to help as well

9. How many crabs are in the tank and about how large are they?
I had 5 S/M purple pincher crabs until the end of December. Then I took in a friends purple pincher crab because his tank mate died and he wanted to re home. About a month later, that crab passed. Then, every few weeks since my crabs started passing. Another crab passed today, leaving me with 2 crabs.
Curly - What were the circumstances around their deaths? Were they on the surface or buried? Were they in a shell or out? Where were they located when you found them deceased?

—they were all on the surface. All we’re in the shell except for one.

10. How many extra shells are usually kept in the tank, if any?
I also have multiple shells for each crab
Curly - HCA recommends 3 to 5 extra shells per crab. Did your crabs change shells while they were alive?

—I have about 15 in the tank at a time. I change them out from time to time. All of my crabs changed shells while I had them. The one crab that passed out of the shell stayed in his painted shell that he came in until the end, he switched into a natural shell a few days before passing.

11. Have there been any fumes or chemicals near the crabitat recently?

—at most I use an air freshener in the same room as them but I didn’t think it was an issue since I don’t spray near them and also the lid is basically covered with wrap and a towel. I also use flukers de-deodorizer/probiotic spray that claims to help break down waste. I spray a minimal amount about once a week

12. How often do you clean the tank and how?
We did deep clean the tank after two crabs passed. Also, after each passing, we got rid of the substrate in the area around the crab.

13. Are sponges used in the water dish? If so, how are they cleaned?

—no sponges

14. Has anything new been added to your crabitat recently?

—I switch things out very few months with resin climbing stuff. All cleaned prior to adding and all able to be in a high heat and humidity environment. I had mites once and got rid of all wood so things are easy to clean.

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.)?

—no play time, no bathing

16. Please describe the emergency situation in detail.

I’m looking for some help on WHY they keep passing. I’m trying my best to take care of them and I don’t understand it.
Curly - I posted a few more questions above (and pasted your answers into the appropriate sections) to try to get more info about your situation.

They should be molting a lot more frequently than what you've seen. It may not have anything to do with the new addition and may have everything to do with just the timing.

I'm not seeing anything here that is a screaming problem. There's nothing in what you've provided that's any sort of giant red flag of death. It could be something small like with the water conditioners Curly pointed out, those can sometimes add up over time unfortunately.

I'd be immediately suspicious of the substrate if this was my tank. You've kept it moist and have changed it out though, so even that isn't like a glaring issue. Did you buy the replacement substrate from the same places? I'm wondering if a new bag of sand from a different store might entice them into molt.

I use playsand from Home Depot (100lbs) and eco earth from Amazon. It’s been from the same places. Do you think I should change the proportion of sand to eco earth? Right now I use mostly sand. And do you have a salt /fresh water conditioner that you think is best? Thank you all for replying as well!! I appreciate it sm

Here is everything (and more LOL) that you need to know about water and the various brands:

https://www.hermitcrabassociation.com/p ... 27&t=92553

You spray your sub down, but your humidity is a bit low. Is the substrate sand castle consistency all the way to the bottom? One easy way to figure this out is to put something long and round like a chop stick down into the sub, right next to the glass where you can see it, all the way to the bottom. When you pull it out, does the hole stay the shape of the chop stick or does the substrate cave in on it? Is there any water pooling in the bottom of the hole?

When I poke a hole, it does not leave a hole. I’m guessing that means my substrate is not wet enough. Any recommendations on how to keep it really moist ??? Considering my daily sprays are not working. Should I pour water on the substrate? I’m worried that may collapse any tunnels if crabs molt

Is anyone underground right now? If not, you can add water and mix up the substrate. If crabs are underground, you can add some water along the edges and allow it to seep into the rest of the substrate.

No one is underground now but I’m thinking long term. If this happens again, I’ll have to re soak the substrate. Should I always just pour water on it all? Since spraying is not enough