HCA: Hermit Crab Association

Well I have 3 hermit crabs that I've had for a couple of months now.
We have a white, red, and green/ grayish one.
Well after awhile all of them molted a couple times.
Recently the green / grayish one molted again, was still molting or eating the leftover exo, and the white one was just digging around and all, and I didn't think of it at all, well this morning I went to change the light and refill the water, and the white one had found the green / grayish one under the tree in the coconut, and was trying to roll him over, and i thought he was just messing with him....
Well when I cam home from work today, to check up on them, and I saw a white body...... It was the white hermit crab.....
So I freaked out, and took the top off, and picked up the tree to expose white hermit body, and found his empty shell in the hole where the green / grayish was molting.
The red one has been chilling on top of the tree the whole time.
So I went to clean my car (car enthusiast),and came back and saw that the green / grayish one was on the back side of the red hermit on the flat area where it looks like a rock on the tree....
I thought the green / grayish hermit was about to do something to the red.....
The red is half the size of the green / grayish hermit right now.
All i have is the 10 gallon tank...
What do you guys or gals think the green / grayish hermit was doing to the red one??
Thanks for your reply.

l'm trying to understand. Are your hermit crabs always surface molting? If so, it would be helpful to fill out the template from the emergency forum so we can help figure out why they may be doing that.

If that is the case and you would like to fill out the help template here it is:
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. What type of housing are the crabs kept in, what size is it and what kind of lid is on the housing?

8. How many crabs are in the tank and about how large are they?

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

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

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

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

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

14. 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.)?

1. What kind of substrate is used in your tank and how deep is it? One side is coconut, and the other side is sand.

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?Humidity gauge is over the coconut side, and temperature is on the sand side. Humidity is at about 50%, and Temp is at about 75

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

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 salt and fresh water.

5. What kinds of food do you feed and how often is it replaced? Hermit crab flakes.

6. How long have you had the crab and what species is it, if known? A couple of months, from tawian??

7. What type of housing are the crabs kept in, what size is it and what kind of lid is on the housing? a 10 gallon tank

8. How many crabs are in the tank and about how large are they? 3 crabs, they are just babies??

9. How many extra shells are usually kept in the tank, if any? there are a total of 3.

10. Have there been any fumes or chemicals near the crabitat recently? No.

11. How often do you clean the tank and how? about every 2 months.

12. Are sponges used in the water dish? If so, how are they cleaned?no sponges

13. Has anything new been added to your crabitat recently? no.

14. 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.)? none.

I'm not entirely sure what the situation that you're asking about in your original post, but I'd just like to note that you should definitely get your humidity up to 70-80% in the tank as the crabs need it to breathe properly, and you should try to have at the very least a couple of suitable shells laying around for each crab - which will reduce the risk of shell fights among your little guys. Additionally, it's good to feed them a variety of fresh foods, such as fruits, vegetables, proteins, etc. A safe and unsafe food list can be found in the food and water section of this forum. Mine especially like strawberries and peanut butter!

Also, what kind of salt are you using, and what are you using to dechlorinate the water?

ginapo wrote:I'm not entirely sure what the situation that you're asking about in your original post, but I'd just like to note that you should definitely get your humidity up to 70-80% in the tank as the crabs need it to breathe properly, and you should try to have at the very least a couple of suitable shells laying around for each crab - which will reduce the risk of shell fights among your little guys. Additionally, it's good to feed them a variety of fresh foods, such as fruits, vegetables, proteins, etc. A safe and unsafe food list can be found in the food and water section of this forum. Mine especially like strawberries and peanut butter!

Also, what kind of salt are you using, and what are you using to dechlorinate the water?

Yeah, I've gotten it to 70% before, but it sits around 50% to 60% humidty.
I have 4 other shells for them to pick out.
Food wise i have been feeding them crushed pecans before. I need to find other stuff to feed them.

I'm using calci-salt?? I'm using the delchlorinate solution from PetsMart and Petco.

It really is important to get the humidity up if it is that low. Anything under 70% will cause serious health problems. Some things to try are:
You may need to add more water to the substrate if it's too dry.
Try to cover the lid somewhat well so that it holds in moisture. This will restrict air flow, so make sure to open the tank several times a day for fresh air!
Have you calibrated the hygrometer lately to make sure it's reading properly and it really is 50%?
Are you using playsand or calci-sand? Calcisand is hard on the humidity and can be dangerous for the crabs.

Also, is the substrate deep enough for them to bury? It could be that the crab you found had to molt on the surface and the others smelled it and couldn't resist.

It does sound like they may have eaten the crab you found since they are only getting flakes as their diet. They are very much like humans in that they need a range of foods in order to stay healthy, and if they aren't getting it they will eat each other to stay alive. There are many options available in the fish and reptile section if you don't have human meats around to give them. Mine love the Fluker's Turtle Medley treat, and it offers a range of proteins all in one place with a mixture of crickets, shrimp, and mealworms. Fresh fruit can be frozen in small pieces so that dinners are easy to give. Tree leaves from Maple and Oak are also huge hits and are very good for them.

Do you know if the shells you have for them are the right type? If the other crabs are wearing better options, they will try to take the shell away, which can lead to injuries. 4 shells can be enough, but only if they're the right types and sizes.

If I had to pick something that would cause aggression it would be the food or a shell problem. I don't feed any "hermit crab food", they are omnivores, just like us, so as long as you provide a variety of foods you can feed them yourself. At each feeding I cut up one vegetable, one fruit, and one meat, then add eggshell for calcium. Occasionally I'll feed some oats soaked in EVOO. It's really simple to do. A crab who is not getting adequate protein and calcium may turn to his tank mates to make up for it, so get some meat into your crabs. Choose raw meat or cooked, unseasoned meat.


Make sure your spare shells are the proper size and are actually hermit crab friendly. I know our petco sells shells that hermit crabs cannot get into, it irritates me so much, the openings are too narrow for a crab to get his body into. So you want to make sure that is not the problem. The shell should be just slightly larger than the shell the crab is in now (assuming his current shell fits well and is not huge or very tiny on him). A crab who does not have adequate shells to choose from will rip another crab out of his shell to use it and this can result in a dead crab.