u/Double-Ad7635

I found my little guy Jerry curled up next to a shell this morning that he was clearly trying to move into, he doesn't seem to have any physical damage and our other crab moved into a new shell just fine this week. Both are about the same age, what could have happened? They had good humidity, atleast 3-4 inches of soil and sand, there was food, and his two soaking areas. He wasnt very old and im not sure why he didnt move into the shell sooner, it was the same kind of turbo shell he had just bigger. Any advice? Do I need to get a new friend for his tank mate sooner rather than later? Im so sad he was thriving so recently and it was devastating to find him like this.