Naked Ecuadorian hermit crab! Help!

[Heatherleighhh]

1. What kind of substrate is used in your tank and how deep is it?
Sand, eight 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? 
Two of each gauge, both gauges read 80/80 they are located mid tank an stay pretty consistent

3. Is a heat source used in the tank? If so, what? 
One of those sticky outside glass heaters on one end. An light on top on the other side

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)? 
One fresh an one salt. Treated with treatments they sell for hermit crabs same with the salt

5. What kinds of food do you feed and how often is it replaced? 
I've been making my own food for two years, it's changed daily

6. How long have you had the crab and what species is it, if known? 
This was a rescue I've had for about two months. Ecuadorian

7. Has your crab molted, and how long ago did it happen?
He molted about a month ago.

8. What type of housing are the crabs kept in, what size is it and what kind of lid is on the housing? 
55 gal glass aquarium. Glass lid

9. How many crabs are in the tank and about how large are they? 
12. One jumbo, one tiny. The rest are in between a baseball an golf ball size

10. How many extra shells are usually kept in the tank, if any? 
Over 25

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

12. How often do you clean the tank and how? 
Every so often when no crabs are buried I'll mix the sand around a little. An wipe the glass down inside

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

14. Has anything new been added to your crabitat recently?
Nothing new 

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.)?
This crab molted came out for a couple weeks an then went back underground. He did change shells in that time. I've had problems in the past with ecuadorians doing this same thing. They unfortunately died afterwards. Also to note I've never had any problems with any being aggressive. The tank is large enough to everybody to have their own spot an enough shells never cause a fight

16. Please describe the emergency situation in detail.
I woke up this morning to notice he was naked. Did the usual steps to try and get him back into his shell with no luck. I'm not sure what else I can do

[mool]

Oh no! Do you have him isolated? If not, can you isolate him with his shell and a couple others of similar size?

[DragonsFly]

I've never had an Ecuadorian; I understand they prefer warmer temps than PP's, though. Someone who has them will chime in soon, I'm sure.

What I can address are a few things:

1) 12 crabs in a 55g, including very large and jumbo sizes, is in my opinion overcrowded. This may be exacerbated by having more than one species (I think you have both PP's and Ecuadorians, is that right?); because they may have communicative/behavioral differences that cause issues when in forced proximity.

2) 8 inches of substrate is not nearly enough for jumbo crabs (although that may or may not be contributing to this particular problem, it is likely to be an issue in the future).

3) Given the absolute number of crabs and shells, there seems to be a shell shortage, which definitely could be contributing to this problem. The good rule of thumb is to have three extra shells per crab, one a little smaller (opening size, not overall shell size!) than what the crab is in now, one the same size, and one a little bigger--for EACH crab--and of course, these should be the preferred type of shell for the crabs in question. If there are crabs competing for shells of a similar type and opening size, and there are not enough (or not enough that are "good" by the standards of the crabs), that can result in shell-stealing aggression, which can result in shell-less crabs.

[DragonsFly]

Another possible problem: you say the water sources are "treated with treatments they sell for hermit crabs"--most of the stuff sold specifically "for hermit crabs" is useless and/or actually harmful. You need to either use filtered spring water or dechlorinated tap water for the fresh water, and a product for marine salt water, like Instant Ocean or Oceanic, to make their marine salt water.

Speaking of things sold "for hermit crabs" and being useless, I've often seen shells sold "for hermit crabs" that are not shells they can or will use. So, check the Shells forum for the types of shells that PP's and Ecuadorians actually like and can use, and make sure that you have enough of each (three per crab, as described above) for each PP and Ecuadorian you have.

Finally, there was a LOT of talk a couple of years ago about Ecuadorians just plain being more aggressive, and more tricky to keep alive through molts, than PP's. Not everybody had these problems, but enough people did that separating the Ecuadorians from the PP's was a thing a number of people who had both types of crabs decided to do, just for their own peace of mind--and so the Ecuadorians could have slightly different conditions and more easily-re-settable decor, so the E's could "trash the tank" more. Considering the crowding issue along with this, that might be a good idea for you, too, to consider setting up a separate tank for the E's.