Sadistic Crab --- Ethics Question

[hammerhead 69]

I'm brand-new to the salt. In the planning phase. However, a friend of mine has this big, horrible crab. I saw him do this to two other crabs (hermits, I think). He took the smaller crab's shell in one claw and pulled it out forcibly with the other, took a couple of bites of him , killed him, and left the meat and did it to another crab.
Is this...safe and natural for a reef, or is it abusive? My buddy just laughed it off. (I'm leaning toward herbivores and inverts, not predators).

 

[hammerhead 69]

This wasn't like the Discovery channel where they do it for nourishment, this was straight up murder, I mean this things was like the Michael Meyers of crabs.

 

[chaoticdamsel]

Is it natural? Yes. Cycle of life, survival of the fittest, whatever you want to call it. Is it something you want in your reef tank? Probably not.
There's no way to tell what kind of crab he has based on your description, but I'd never keep anything with that kind of behavior in my reef tank. The hermit crabs, snails and such that you put into your tank serve a purpose. They help keep your tank clean. Keeping something in your tank that actively hunts them down and kills them is counter productive.
Unless, of course, your whole intention is to keep an aggressive or species specific tank. That's a different story all together.