crab digging under tank fixtures?

[harleyhamilton1]

hi! it’s not uncommon for my crab to go rogue for a few days- he usually will climb behind the heating pad I have on the wall that hes peeled up so he can fit behind to keep extra warm (he does have a heating lamp- he just prefers it even warmer than the heat of the lamp)
but today I genuinely thought I lost him, he had piled massive amounts of sand behind the heater and had clearly been doing a lot of digging in that area, but could not be found
until I lifted one of his bowls to fill it- he dug an entire hollowed our pit and was sitting in it, directly underneath the bowl. it’s roughly 6 times his size (and he’s slightly larger than a golf ball) but the water bowl was the “roof” of his new hole.
should I be concerned he dug a whole cave? how do I provide a way for him to come out of the hole? is he just digging for fun or is he molting?
I wasn’t sure if it was molting, due to the fact the hole was so large compared to his body.

[aussieJJDude]

Hello, and welcome to the board.

Sounds like a fun crab, and to cut straight to the point, yes, he could be moulting. Their moulting caves are fairly sizable, which is why many reccomend a deep sand bed and understocking the tank. I've dug up a moulter (around goldball size, maybe slightly smaller (?)) where the cave was around 6 inches in diameter. So they do have big caves to moult.


I would also encourage you if you haven't already to situate the heat mat on the outside (side) of the aquarium, many usually reccomend the back wall. Crabs have claws, and they can be rather effective for snipping through plastic exposing wires (which in a high moisture environment like the crabitats, I would imagine would be a fire risk).

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