Vanished Crab? Not just buried...

[remusandromulus]

When I was gifted my crabs in early June, I was given two of them, as we all know they are social animals. Both would be considered small-sized, with Romulus being just slightly bigger than the other. I originally had the 10 gallon kit that PetSmart sells. About a week after I moved my crabs in, the smaller one went under (by the way, Romulus had a green-painted shell and immediately swapped into a spotted turbo after moving in. Shorty had a red-painted shell and went under in it). I didn't worry about it because I knew it was most likely stress or maybe even exploration. When I saw no trace of him after a month, I assumed he was molting and didn't expect him to be up for another month or so. Totally fine.

At the end of August, I bought the 20 gallon that I have now. I was in the process of setting it up when I noticed that that day, the red shell was sitting on top of the sand, empty. I thought he had finally finished and swapped, but I thoroughly checked every single shell in the tank as I moved them into the new one and I couldn't see him. I was worried he was shell-less. I took a soft bristle unused paint brush and spent 5 hours (literally) slowly brushing the sand as delicately as possible searching for him. By the time I cleaned out the whole tank of its sand, I found no body but three or four pieces of legs, a claw, and what looked like crushed orange exo. I was so worried because to me he had just disappeared, the fact that I couldn't find any kind of body really confused me. I checked outside the tank as well to see if he had escaped despite the lid having a lock on it but I didn't find anything.

I've read that sometimes if a crab is molting and the sub isn't deep enough (I believe I filled it to four or five inches) other crabs can smell them and attack/eat them. Could this explain why my crab went missing? I couldn't think of any other reason at the time but I guess it wouldn't hurt to ask if anyone else experienced this.

Since the move Romulus has definitely made himself at home. He's made a nest in the top of the coconut climbing wall, pulled off a chunk of wood off his driftwood and made a bed out of it, and at one point he made 5 holes in the ground all over the place. I am also worried that adding a new crab will throw off the balance of his territory and will result in a fight or another vanished crab. I've taken a liking to Romulus and I'd be crushed if he's one of the few crabs that don't mind being by themselves.

[curlysister]

A crab can pass away underground, and with the heat and substrate can compost away into nothingness in a short amount of time. So it could be that another crab came across the crab while molting underground, but it is also possible that he passed away of post purchase syndrome (kind of a catch-all phrase for when a crab passes away after we get them before they molt at least once) and disintegrated.