Hermit crabs killing each other

[DreadedReefer]

I have a handful of Hermits are one day I saw two of them, I thought they were mating maybe, but it turns out one just killed the other. He/she did not take over the shell because it was much smaller. I know it could not have been for the shell because we have plenty of larger shell in the tank all different sizes. Are they killing for sport? I feed at least 2 times a day so I know/hope is not for food. Plus.... He/she just took the other crab out and just "THIS IS SPARTA" of the "cliff"

 

[Txplicit]

Some species of hermits will attack each other for territory and supremacy. Red legs and blue legs don't get along. You can either let them fight it out and watch the ammonia spike from dead hermits, or fish out the species you don't like.

Is there enough algae for them to graze? They sometimes attack each other and snacks if they're hungry. I usually pin a small nori piece under a small rock that distracts them and feeds them to prevent attacking each other.