Hermit crabs mating for fighting?

[seth16]

This morning before I left for school I noticed that a red legged hermit crab was being pestered by a smaller red legged, and within a few minutes a blue legged hemit joined in, I separated the two hermit crabs but they ended up locked together again. Should I be worried about the larger one?

 

[seth16]

 

[seth16]

 

[Tahoe61]

The larger may be getting ready to molt or has molted and the smaller hermits are looking for a free lunch and home. You can offer them some slightly larger empty shells but hermits are pretty ruthless, they kill and eat what they can.