HCA: Hermit Crab Association

One of my crabs was alone for a bit less than 2 months. I then introduced 3 more crabs, all of which were smaller. My original crab had just molted and was trying around for some new shells. While doing this, one of the new crabs took his old shell. My original crab seems to want that shell back. I witnessed him trying to steal it.

After that I isolated my original crab in fear that he would kill my new crab for the shell. How long should I isolate my original crab? Or is this something that can't be fixed (as in he'll always want the shell back)?

Just some other info: My new crab fits really well in the shell, yet my original crab does not at all. Yet he still insists in going in it. I'm not sure if my original crab is happy in the shell he is in now, or if he still wants the other shell.

Any tips and advice is very much appreciated

Thank you!

how many shells do you have?
if you don’t have at least 3-5 per crab it would help to buy more so they have a wide variety

I have plenty of shells for both of the crabs involved. They are (mostly) all the same type so I'm not sure how much variety there really is. All are different sizes though.

this happened with one of my crabs before and even though i had more than enough shells i bought more and he went to a new shell and was happy