Professional Assassin?

[Bugboy2020]

I'm really mad I didn't record this. I have a 5 gallon tank that is empty besides two hermit crabs. Over the past two weeks, I've noticed one hermit keeps trying to kill the other. This certain hermit was perched on some rock above the other hermit in the gravel. He then looked down, then tipped himself over so he fell on the hermit. He then flipped over his "friend" and started poking his claws inside his shell. At this point I reached in and tossed him on the other side.
What can I do to stop this? (Note: I feed them, even though they're supposed to be eating diatoms right now)

[tc2007]

It's about getting the shell not food. You can get some bigger shells than what they have and put in the tank. Most LFS will give you for free.

[Potatohead]

It's like game of thrones for crabs

[LED Jack]

You always need to keep extra shells in the tank with hermits. And even then that does not guarantee you will not have shell wars.....lol

[Sk8r]

This. It's life and death for them---if they can't get a shell to accommodate their coming molt, they're fishfood, so yes, they do get uptight and desperate.