Hermit Crab behavior

[Sumfingwong]

Not sure where to post this, since its in my fowlr I will put it in this sub forum.

I bought 2 more electric blue hermits for my tank.

As soon as one of the older hermit saw one of them, he made a b-line for one of them and started to attack? it?

Heres a photo I took. They were at it for 3 hours, and I separated them to opposite sides of the tank. A couple hours later, the older hermit made his way to the other hermit again!

I went to my parents house to grab some empty shells from a FW setup I have over there full of shell dweller cichlids.

When I got home, I separated them again and placed the one thats attacking/lovin with the empty shells, he/she checked them out and took off.

Anybody know if this guy is trying to steal the shell? or are they mating?

thanks!