2 of 3 crabs dead in the last month - what to do?

[kattles]

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?
I have a mix of play sand and EcoEarth (~5:1 ratio) that is six inches deep.

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 a thermometer hygrometer mounted partway up the tank wall, as well as an additional temperature probe at the other end of the tank where my UTH is mounted. My humidity is (now) consistently in the 70-80% range, and my temperature is 80 degrees for most of the day with a drop to no lower than 76 at night. There was a couple weeks where my humidity was out of control and always 90% or higher, but I got that under control with some more ventilation.

3. Is a heat source used in the tank? If so, what?
As mentioned above, I have a UTH that is mounted on the back of the 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)?
I have both fresh and salt water available. I use instant ocean to make the salt water, and the dechlorinator is API brand tap water conditioner.

5. What kinds of food do you feed and how often is it replaced?
I have given a mix of fresh and dried/freeze dried foods. I let dried food hang out for 2-3 days since it doesn't mold quickly, and try to take out fresh food within 24 hrs. There have been times that I forgot and was greeted with white mold, but thoroughly cleaned the food dish as soon as I noticed

6. How long have you had the crab and what species is it, if known?
I have/had three PP hermit crabs. I got them at the very end of January of this year.

7. Has your crab molted, and how long ago did it happen?
All three crabs have molted. They all went down near the beginning of February and came back up in March.

8. What type of housing are the crabs kept in, what size is it and what kind of lid is on the housing?
My crabs are in a 29 gallon tank with a glass lid. The lid has a gap in the back so it's not completely sealed shut and fresh air can get in.

9. How many crabs are in the tank and about how large are they?
Three crabs, all are in shells that have 1 inch openings.

10. How many extra shells are usually kept in the tank, if any?
I have somewhere around 15 shells of various sizes in the tank.

11. Have there been any fumes or chemicals near the crabitat recently?
Not to my knowledge within the last month. However about 2-3 months ago, there was mold on my wall in the same room as the tank that I cleaned with some diluted bleach, if that could have affected them.

12. How often do you clean the tank and how?
I spot clean the tank as needed. I used dechlorinated water and vinegar for cleaning the dishes and make sure they're fully rinsed before introducing back to the tank. I had a mold problem and had boiled all wood and other tank accessories to get on top of it about two months ago.

13. Are sponges used in the water dish? If so, how are they cleaned?
I do not use sponges.

14. Has anything new been added to your crabitat recently?
I added a lizard hammock and some plastic vines, which I cleaned before putting in using boiling water and vinegar.

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.)?
I don't take the crabs out of the tank and don't give them baths. I mostly just make sure they have food and water and that the tank temperature and humidity are in range. I've also verified that I do not have any flooding in the bottom of the tank.

16. Please describe the emergency situation in detail.
This isn't necessarily an immediate emergency, but this seemed like the best place to reach out for advice and feedback. As I mentioned above, I have had three hermit crabs since the end of January (almost six months to the day) and all three molted in February. One crab, Maverick, was up for a few days then re-buried himself and I have not seen him since March 17th. My other two crabs, Flip and Puddles, were above ground and seemed fine. Then about a month ago, I noticed that Flip was less active, and came to the realization that he had died in his shell above ground. I left him there for several days to confirm with the death smell, and I was able to shake him entirely loose from his shell and confirmed that he had not molted above ground. Puddles has been less active since Flip died, and I was thinking that was perhaps because he was alone above ground. I was going to ask for advice on introducing a new crab, but got sidetracked because suddenly Puddles was naked in the tank and acting lethargic. I did what I've seen others suggest, which is isolating him with shells about his size and I even attempted to re-shell him (which I still have mixed feelings about because it seems like it can either help or make things worse), but he ultimately did not re-shell and died. Now I'm down to Maverick, who has been below substrate since mid-March, and I have no idea what to do or where I went wrong. I spent hours researching hermit crabs before I got them, and to my knowledge my tank was set up to the specifications that have been recommended so I don't think that it was a temperature or humidity issue. Additionally, this now has me wondering if there's something like bacteria or fungus that I couldn't see? I also don't know whether I should try to gently un-cover Maverick to see if he's even alive. I don't want to just add new crabs to this tank without giving it a thorough cleaning in case something environmental happened. I'm just torn. I know that these things happen, and that I guess we can't really say for sure what the cause was, but losing them both within a month really sucks and really makes me question if I did something wrong. Any advice on how to proceed or suggestions of anything I am missing would be much appreciated.

[JoeHermits]

I don't see anything obviously wrong with your setup.

API doesn't treat ammonia but I don't think that alone would be enough to cause death.

I don't think using diluted bleach near their tank would've been harmful.

I trust they get protein and calcium?

Has your hygrometer been calibrated?

Otherwise you may have just had bad luck with this batch.