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?
Eco earth. Lowest spot is 3 1/2 inches highest is 5 1/4 (I’m getting more soon (part of the problem)

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. They are located in the middle. Temp is 68/74 humidity is 75-ish

3. Is a heat source used in the tank? If so, what?
I have a heat lamp and two low powered heating pads

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. I buy from PetSmart

5. What kinds of food do you feed and how often is it replaced?
I feed a brand called thrive it’s replaced every other day

6. How long have you had the crab and what species is it, if known?
I’ve had this crab for four months two days ago I got two more (totaling four) all are purple pinchers

7. Has your crab molted, and how long ago did it happen?
Has not molted in my care

8. What type of housing are the crabs kept in, what size is it and what kind of lid is on the housing?
This crab lived in a cork house with another he was in a tank with at PetSmart

9. How many crabs are in the tank and about how large are they?
Four crabs all medium

10. How many extra shells are usually kept in the tank, if any?
I keep about 7-10 if possible

11. Have there been any fumes or chemicals near the crabitat recently?
None

12. How often do you clean the tank and how?
Every other weekend and occasionally on Wednesdays. I use a scoop to get all of the poo out I clean both water dishes and clean out the food dish (it’s a shell so I boil it again too)

13. Are sponges used in the water dish? If so, how are they cleaned?
No sponges are in the tank (I had one in for about a month before I saw it wasn’t helping with humidity)

14. Has anything new been added to your crabitat recently?
I have added a log house, and a few artificial plants

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.)?
The new crabs were getting along but the biggest crab is now in my old crabs shell while his is abandoned

16. Please describe the emergency situation in detail.
I have just recently got two more hermit crabs and everyone was getting along. I monitored them for 12 hours ( six day six at night) and I thought they were fine. I woke up and could not find my one (who lives in the cork with my other old one) anywhere. I dug around the topsoil a little bit there was no mound or hole. I see no body parts there is a smell but I believe it’s the bedding



Thank you everyone for all the information and help. I have just found his/her body. I believe he/she came up from molting too early and the others ate him/her.
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Sorry mods, can you please delete post? Made in error.

First things first, DO NOT dig in your substrate for the crab. This is fatal to them. As long as your lid was not left open, and there are no gaps they can exit through, your crab is still inside your tank. They often dig down and hide as they are prey animals, and this is absolutely normal. When I first get any crabs, they usually disappear for a few months until they feel it is safe to come out. It's their way to de-stress.

Based on your tank conditions, it's possible there was a shell fight as there's not enough shells. You need at least 4-5 shells per crab that's a little smaller and bigger than their current shell. If your crab took a different shell. It could have dug down into your substrate.

In the meantime, here's a few care sheets that you may find helpful to further improve the crabitat.

Basic Hermit Crab Care for all Species
Post Purchase Syndrom
Commercial Food
Hermit Crab Nutrition
Water
Humidity
Substrate
Tank Size

Is it possible the crab may have changed shells and then dug down? Even if you found no holes, that isn't always the case; sometimes they leave the evidence behind, but they're usually pretty good about covering up their tracks. Never dig for a crab unless it's an emergency, though (flooding, bacterial bloom), because if you come across a molter, that can do serious harm to it.

And although this is an unlikely scenario, considering there is no evidence of the crab anywhere, I would still like to warn that cannibalism could also be possible. If a hermit crab isn't receiving the proper nutrition, it may turn on its tankmates. If you're feeding pellets, and only pellets, they may end up seeking better nutrition through other means.

Speaking of pellets, commercial hermit crab food isn't healthy for them to eat. They're filled with preservatives and dyes, and in the long-run those will take a toll on the health of your crabs. I would ditch the pellets as soon as you can.
Check out this list of safe foods: viewtopic.php?f=25&t=92557
And one of my favorites, an in-depth post about what makes up their diet: viewtopic.php?f=25&t=92554

Things that are probably unrelated to why the crab possibly went missing, but could help to know more details about or be improved upon:

- How many gallons is the tank?

- What brand dechlorinator are you using for your pools? And what brand of salt do you use to create your saltwater pool?
Water and water conditioner marketed for hermit crabs are not efficient, and again, oftentimes are created with added contents that might not be safe for them. A lot of people here use Prime as a water conditioner and Instant Ocean for salt.

- 68 is a little on the lower side for a temperature. Try to keep it 75-85. You can insulate the tank with blankets and pillows, but avoid covering your UTHs unless they are the type that are safe to insulate.
75-ish for the humidity isn't too bad, but above 80% is ideal. Heat lamps have a tendency to zap humidity, and if you're using a screen lid that will do it too. You can wrap the lid with plastic wrap in an attempt to keep in the moisture, but of course avoid the light.

- Try to offer 3-5 shells for every hermit crab in your tank. The more the better! Make sure they are the preferred shells of the specie you have (purple pinchers typically like turbos) and that they are all around the same size for the crab to fit in comfortably, with some variance.

I hope your crab shows up eventually! He could just be down molting in a different shell, and I hope that is the case. Above all, I'd definitely look into switching up their diet to avoid any potential cannibalism (I really hope that hasn't been the case, though again, you'd probably still have evidence of the crab). Good luck and best wishes to your crabbie!

Thank you so much for this information and all the help