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?
A mix of play sand and eco earth. I try to do the 5.1 ratio, but don’t get super technical with it, just guesstimate.

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 Acurite digitals. One sits on the bottom near the pools and usually reads temp (80-83) and humidity drops down to 60% if I don’t mist multiple times a day. The other one sits near the top of my topper tank and usually reads temp (80-83) and humidity (75). I also recalibrated them recently and they read correctly.

3. Is a heat source used in the tank? If so, what?
Yes/Ultratherm heaters on the whole back of the tank. Goes to about 1” under the substrate.

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)?
They have kritter keeper pools (1/2 gallon). Fresh is treated with a water filter I have (it is better than bottled) and salt is Instant ocean (1/2 cup per gallon)

5. What kinds of food do you feed and how often is it replaced?
I feed all kinds of fruit, veggies, nuts, and grains. I am trying to give them meat more often. They only get it now about once a week. Food is replaced every night.

6. How long have you had the crab and what species is it, if known?
The eldest is going on 4 years with me and they are all purple pinchers.

7. Has your crab molted, and how long ago did it happen?
2 currently down.

8. What type of housing are the crabs kept in, what size is it and what kind of lid is on the housing? Just upgraded them to a 55 gallon with a 20 high topper. One Lid is an Aqueon with an LED light. I made some modifications (gluing plexiglass to the opening so humidity would stay better). This lid is on the pools/lower side. The other lid (on the topper) is a screen with plastic wrap and plexiglass sealing it.


9. How many crabs are in the tank and about how large are they?
7 purple pinchers. 2 small and 5 small/mediums

10. How many extra shells are usually kept in the tank, if any?
15-20 I try to rotate them so the crabs don’t get bored.

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

12. How often do you clean the tank and how?
I spot clean every week, including changing water and rearranging the decor. I only deep clean if there is a serious reason to.

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

14. Has anything new been added to your crabitat recently?
Some new pieces of grape wood and a hemp net.

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 owned crabs for the past 16 years. I just learned what care requirements they really have and how to take proper care of
them about 4 years ago. I was doing well with my 5 smaller crabs in a 20 gallon high, but ended up taking in 2 rescues and decided it was time for an upgrade. They just got a 55 gallon and I used the old 20 as a topper. The issue is that I can’t seem to keep the humidity high enough, which has never been a problem before. As I stated above, both lids are sealed pretty well, and in smaller tanks I used both lids without issue (usually having humidity in the high 90% range). In an attempt to increase the humidity I added 2 1/2 gallon kritter keeper pools with bubblers and a wet moss pit, but they have not helped much. At this point the substrate is REALLY dry and I think any humidity I added just gets absorbed into the substrate. I think that if I re-wet
the substrate my pools and moss would have a bigger effect, but I have at least 2 crabs currently molting. My questions are:
1. Do you think the dry substrate could be absorbing the moisture and would re-wetting it solve my problem?
2. Is it necessary to disturb my molters for the greater good (only 2 molting and 5 suffocating at the surface)?
3. Do you have any other ideas for boosting humidity?

Yeah, it really sounds like the substrate lost too much moisture so you're kind of stuck in a neverending battle.

If you have a humidifier, even a room humidifier for the house, it is a great way to rewet a mass of substrate without having to touch it. I just picked up a mini portable one that takes water bottles at Walmart for $15 to have on hand for this kind of situation.

Spraying the top layer of the substrate down heavily and then waiting a half day and doing it again, until it's properly moistened, will work as well. It won't bother molters if you do it evenly and in stages.

I've always just poured in water when things got too dry, but I had a good idea of where the molters were and just sort of aimed around them. This can cause issues if the water settles in the lowest and easiest path, which can be molting caves.

The key with all of these is to have the tank sealed up tight to hold in what you are adding, not to add too much moisture at once to prevent flooding, and to wait a bit so the substrate evens itself out throughout it's mass before adding more.

Dry substrate will definitely zap the humidity. You'll want the sand to be a sand castle consistentcy, so once the sand is remoistemed, the humidity should bounce back. Others on the forum pours some water along the side/corner of the tank.

I personally spray all my driftwood so it absorbs moisture and remaining will run into the sand, and also also on the sand surface.



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