HCA: Hermit Crab Association

I have 2 hermit crabs and I wanted to get 1 more to add to the tank. My other 2 are buried and have not come up for about a month. Can I introduce another crab while they are buried or should I wait until they come up? What is the best way to introduce them?

Here is some background knowledge:
I have had these 2 crabs for about 1.5 years. They are both about 2 inches long (including their shells) and have a 1/2" shell opening.

If the substrate is of appropriate depth and the tank size is large enough to accommodate the newcomer, its fine to add another crab.

Thank you! We got another crab. We dipped it in the freshwater dish and placed it in the enclosure. It's a little bit smaller than the others so hopefully that will be ok once the other two finally come up (when??). So far so good. Thanks for your response!

I have crabs of all sizes together, so no worries there. Congrats on the newbie!

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