Crab deaths, I don't know what I'm doing wrong

[con_dwy]

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?
Play sand and cocofibre, 8:1 ratio

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?
70-90 percent humidity 23-25 degrees

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

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. Dechlorinated with fish tank conditioner. Salt from hermiesdelights.com.au

5. What kinds of food do you feed and how often is it replaced?
hermiesdelights.com.au every few days

6. How long have you had the crab and what species is it, if known?
Australian, a few months

7. Has your crab molted, and how long ago did it happen?
yes, a few months ago

8. What type of housing are the crabs kept in, what size is it and what kind of lid is on the housing?
Sealed lid, 50 gallon terrarium.

9. How many crabs are in the tank and about how large are they?
2 dead, buried outside not in tank.
2 molting, unkown if alive.


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

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

12. How often do you clean the tank and how?
never done a full clean

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?
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.)?


16. Please describe the emergency situation in detail.

I'm just overwhelmed and I don't know what to do. 6 months ago I bought 3 crabs, one large, one small and one medium.
I kept in a 80 x 48 x 50cm terrarium, 6 inches of substrate (playsand mixed with coco fibre). They have both fresh and salt water, I heated it and sprayed it to keep humidity up and fed them food from hermiesdelights.com.au.

Soon after getting them the medium one and small one went down to molt. The small one reemerged after. the medium still has not. I'm not sure if its alive or not.

The large one died a few months ago. It used to be active and explore the enclosure, but in the week leading up to its death it just stayed huddled against the glass where the heat mat was. One day i picked him up and moved him onto the food when I gave new food. The next day they were dead.

This week the same thing happened for the small one. It had become lethargic and didn't move much, just stayed huddled against the wall. Looked greyed like it needed a molt. Last night I changed the food and placed them in there. This morning I found it dead. I'm really just lost. I feel like a monster and that I killed them, but I tried my best and I don't know what I did wrong. I just feel so guilty. After the large one died I purchased a second small one and that one is molting right now, potentially with the medium. Just please give me advice, I feel so guilty and don't know what to do. Now i'm worried they weren't dead and I killed them by burying them with dignity, I just feel overwhelming guilt and regret ever making the decision to buy them I have no idea how to fix this situation.

Pictures of latest dead crab and tank: https://imgur.com/a/GyCUsGH

[curlysister]

Your conditions look really good. Unfortunately, crabs go through so much before we get them, that they often don't survive even if we do everything correctly. They just don't have the energy to overcome the previous conditions.
The crab in your photo is dead. Do not second guess yourself at this point. You did not bury a crab that was alive.