Naked hermit crab, wont even look at new shells

[BlueElectric]

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?
7ish inches deep, play sand and exo earth 5:1

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?

located in the center-ish of the tank, usually about 78°F-85°F and 80% humidity

3. Is a heat source used in the tank? If so, what?
two under tank heatpads on the back of tank with insulator alon back to keep heat in, with thermometer thing that turns heaters off if the temp hits 85°

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)?

tap with seachem prime, and tap with seachem prime and instant ocean

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

New food daily, mixes from Hermit Grub rotated, plus some fresh stuff, just whatever I happen to be eating- like a blueberry or some egg with shell, a pea the other day, etc

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

2 crabs, one I've had for 5months and the other I got yesterday

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

The first one has, came back up in September

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

55g tank, with hinge lids and saran wrap to keep humidity level

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

2, they are the same-ish size (this is the problem)

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

6 of appropriate size and 2 bigger ones and 4 smaller ones

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

no

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

just gentle raking of leaves if they seem to be getting yucky, and I move the moss back to where its supposed to be every once in a while

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?

a new crab

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.)?

no

16. Please describe the emergency situation in detail.

I got a new crab yesterday and read a lot about what do with a new crab, it had been well taken care of (or so I was lead to believe) at ita last home and seemed anxious but healthy. I watched it for hours to check for any signs of reasons it should not go in with my current crab. I notated that it seemed bigger than my current crab, but not by much. I noted that it could not fully retract into its shell. I put all the correct size and bigger size shells into a small container with it for 3 hours (it also had food and water during this time) and it did not seem interested. I didn't have a way to keep it safely in a separate container for long, so I placed it into the enclosure, as a lot of people said they just put them in and it's no big deal.
This morning I woke up very early (was only asleep for four hours) to see that my original crab had seemingly forced the new crab out of its shell to steal it. I watched the video back and it seems that the new crab didn't even try to stay in its shell, but got out pretty much as soon as the original crab showed interest in the shell. When I woke up they were both just at the food dish eating together, though the new crab was still naked.
I have since moved the new crab into a critter keeper that is inside the 55gal (with lid on) and put all the shells in there and some food and a bit of water but it has not attempted to get into a shell. It's been 2 hours or so and it hasn't moved much (its responsive if it sees movement it will shrink up, and it has reoriented itself to a comfortable position but nothing besides that.)

I don't know what to do and I'm scared to touch it (I scooped it up by digging the whole sand around it and lifting gently to place it into the critter keeper). I feel horrible that I have endangered this new crab I was meant to be rehoming and I am at a complete loss as to what I should do now.

[curlysister]

Have you read through the care sheet yet? It gives pretty detailed instructions on what to do. The container with shells should be small-ish and not have anything to distract the crab - only shells, no food etc.
What type of shell did the new crab have that was stolen? Do you have any that are the same type and similar size?