Trying to solve the mystery of my crabbies deaths

[NikkiS]

1. What kind of substrate is used in your tank and how deep is it?

I used coconut fiber & the sand substrate from The Hermit Crab Patch & it was about 8 inches deep throughout the tank.

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, I had two separate gauges that were located in the center of the tank towards the top. The temp was usually 75-80 degrees & the humidity was usually between 75-90 degrees.

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

I had one heat pad on the side of the tank & one underneath to keep the heat up. Both pads were on the same side 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 had both fresh water (distilled Deerpark) & salt water which I got the salt from The Hermit Crab Patch-Instant Ocean mixed with Deerpark water 1/2 cup to one gallon of water. Both dishes were big enough for the crabbies to climb into & soak.

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

I'm a big fan of the variety of foods from The Hermit Crab Patch so I had just about everything they sell. Main ones being Surf & Turf, Soil diet, wild flower mixes, calcium powders...I actually think I have every food variety from them. I changed the food at least every other day. They did get some fresh veggies as well.

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

I had these crabs for over 4 years two were PPs & I believe the third one was ecuadorian

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

The crabs were in a 20 gallon fish tank with a regular fish tank lid with lighting

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

Only 3 crabs & the 2 PPs were medium on their way to large & the third was a solid medium. I was preparing to build a much larger crabitat for them.

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

I put about 12-15 choices for them since my crabs really enjoyed "shopping" & would rotate them out with other shells about once a month


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

No.

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

It gets scooped once a week, once every 2-3 months I would take all the substrate out, comb through it for food bits & what not, put it in the oven, replace what was needed & would use dish soap for the tank & rinse really well with fresh water, dry it & then replace everything for a nice "remodel"

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

No.

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

The only thing I can think of is I put fresh moss in the tank from someone who has a farm in Arkansas & doesn't use pesticides or anything like that & I put that in maybe a few weeks before all the weirdness began. I switched who I was using because the moss I was getting kept having cricket eggs in them & crickets are super annoying, even the crabs were getting annoyed with their constant chirping! It was pillow moss which was their favorite type.

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.)?

I don't think so. They were very active crabs & really got along well.

15. Please describe the emergency situation in detail.

It started around June when it seemed like they were getting prepared for an epic molt. They were emptying their water dishes everyday & I googled that & read that sometimes crabs will take in excess amounts of water for their molts so since all 3 of them were preparing I wasn't too concerned. I did think it was odd that all of them were doing this but I figured they knew what they were doing. Then I never saw them come back up. On the 2nd story is a shower caddy filled with coco fiber & moss & the small guy's shell was just hanging out on top but he was no where to be seen. I know you shouldn't dig for them because you could disturb them so I let them be. I kept changing foods & waters & misting the tank but never saw any activity. By mid September I had a good idea where two of the crabs were buried so I gently dug around them. One was in his shell & looked pink like he had molted but wasn't moving. The second crab was kind of hanging out of his shell, look pretty gray & was moving very little. I felt awful for disturbing them & even worse when my one guy was moving a little & I thought I had ruined the molt for him. I have read on here & other sites that just because the crab isn't moving after a molt doesn't mean they are dead, molting is just stressful to them. So with some hope (and mostly denial) I covered them up & waited. My husband finally convinced me it was time to dig them up a few days ago (my denial lasted quite some time). The two were in the same positions they were in when I found them. They were completely dried out & the one hanging out pretty much fell out of his shell. The third one was up in the moss pit buried all the way down in the fiber which was about 6 inches, naked & a few pieces had fallen off & he was dried out too. Other than that, there weren't any wounds, or mites, or smells or anything else that might indicate trauma or illness. But I'm also no crab expert so I could have been overlooking something.

I tried to make this as detailed as possible because I am hoping to find out what happened to my little crabbies! After typing this, I want to blame the moss because that's the only thing that changed but I'm just not sure. Thanks in advanced for any insight or help

[hermitcrab24]

Hello,
I want to start off saying I am sorry for what happened

I am not a crab expert (yet ) but I hope I can help.

First off, don't put a heat mat underneath your tank, because the crabs bury sometimes all the way to the bottom, and could "cook" them, in fact, that could have happened to your crabs, but again, I'm not really sure.

Also, you said you used soap to wash the tank, which is not preferred, it is best to use water if your are going to wash the tank. You also don't really need to clean the substrate that often, it really isn't necessary and creates more work for you

I don't know if moss could really effect them, but it is odd that all this occurred soon after it was added.

Hope someone else puts in their input as well.

Good Luck,
Bonnie

[soilentgringa]

Putting a heat mat under the sand is generally a bad idea. The sand acts as an insulator and traps heat. If the heat above the sub is between 75-85 then the sand is warmer because the heat is traveling through it, causing the air to warm up. This can dry out sand causing cave ins and cooked crabs. If your crabs were prepping for a molt and the sand was too warm, they may have attempted surface molts or become dried out.

[soilentgringa]

" Deep cleans usually aren't done unless you have flooding, problem with mites or some other reason that one would be necessary. I've never done a deep clean in a year and a half of owning crabs. I see no need unless there is something wrong where a deep clean will benefit the crabs.<br />As for spot cleaning, all you have to do is take out any food laying around that the crabs carried away from the food dish. Maybe wipe down the sides of the tank to remove sand.<br />Hope this helps <br/>"

This is actually quoted from another post, from hermitcrabdc

[YYWW]

Sorry for your losses. While it is difficult to pinpoint any one thing and know for certain that is the cause, there are definitely improvements that can be made to your tank which can aid in preventing future loss. A lot of your conditions were good. Here are the ones that I found inconsistent with my recommendations.
1. Like hermitcrab24 mentioned the under tank heater (UTH) is not being properly used. UTHs are originally designed for use in lizard/desert type terrariums. The sand is dry and much thinner. When you're heating through 8 inches of sand from the bottom of the tank, the UTH has to work very, very hard to get through all that sand. Sand, being a natural insulator, will get overly hot from the bottom up, making it hard for you to tell that crabs could be overheating. It is possible that a crab would dig down, thinking there was a nice and warm spot, and molt, only to have that spot overheat while they're down there.
11. When I entered crabbing last summer deep cleans were already discouraged. Sand mixed with coco fiber promotes the growth of beneficial bacteria that help break down the waste in your tank, building a balanced system in your tank. When you take everything out for disinfecting you are obliterating the beneficial bacteria that has accumulated. Just keep the surface clean as you like, but allow the sub below surface to maintain it's own balance. It is more beneficial to your crabs, especially when they're molting and move vulnerable. If you do need to scrub the tank or anything inside the tank for a specific reason try to use a 1:1 solution of vinegar and water, and let it air dry. It disinfects and is all natural, and won't harm your crabs. Even if you rinse soap out until the water runs clear, soap may leave a residue that is safe for humans but not safe for our sensitive crabs.
15. So here is just my speculation. But first, my disclaimer. I'm not a scientist or crab specialist. I'm not even very well-read. I have read a lot of HCA (I tried reading ALL of HCA but lost track somewhere and didn't want to go diggin in the archives for my place). I can only compile my knowledge based on everything I learned on HCA (and a couple sprinkles of Wikipedia). This is how I view your situation from my very narrow, very limited eyes:
The crabs were poisoned or sick. They died in different places, but at the same time. Considering your tank conditions it is possible that any of the suggested issues above would have led to their deaths. It's not as if an imbalanced ecosystem or soap residue/fumes are guaranteed to kill crabs, but in a case where crabs are killed, I would expect it to be in this manner.
When you uncovered a molting crab, you also shouldn't put them in the sub and bury them. Crabs molt in caves that they have crafted themselves, and when you put one back in the ground it is just not the same. You could be suffocating or stressing them to death. I'm not saying don't go digging if you really feel like there is an issue. In this case you would return that crab into the ground by swirling a pit for him to fit in, placing him in the pit, and then covering the pit completely with a big, flat object (like a clam shell half or a flat rock).
The moss you got sounds so wonderful. A lot of crabbers use natural moss, plucked from their front yard, with no ill effects (that we know of). However there is a possibility that there could have been any other type of contaminant, virus or parasite on it that you didn't know about. In that case, nobody would have known about it. Aside from washing or boiling it, I'm not sure what else you could have done to take care of anything like that. I guess it's better to err on the safe side and use moss from the pet store or gardening section. But if the moss made your crabs sick, I think that could have happened to anybody. Do people boil moss?
The last thing that seems weird to me is how the crabs were tossing all the water out. I'm just not sure what to make of that. I've never seen or experienced my crabs doing the same. My crabs appear to drink a lot of water before molting. If they really were consistently and adamantly tossing the water out, then I would suspect there was something wrong with the water and they were rejecting it. If there was something in the water that made them sick, it would also fit in with their manner of death. I drink Deer Park, myself, and I submit that it is GOOD STUFF! But where does the Deer Park that you use for crabs come from? How are they stored? My old school mom is always yelling at me for drinking bottled water because she got some spam mail somewhere that told her bottled water leaked plastic into the water and drinking it was like playing Russian Roulette with death.. While listening to my mom is one of the last things I like to do I guess it is possible for traces of plastic to be found in bottled water, sure. To me I don't think it's such a big deal, but what about to the tiny crabs?
I'm sorry for the tragic manner by which you experienced all your crabs die. 4 years is a long time and I hope my own crabs can at least live that long. It's really a shame that you had them for so long and they all suddenly died like that. I hope you can figure it all out and that I may learn from you as well. Best wishes, and let me know if there's anything else I can help with.

ETA: Sorry for writing a book This is what happens when I get in front of my laptop instead of using Tapatalk!!