Killer Arrow Crab?

[Suprised]

Im thinking of getting an arrow crab to hunt down the bristle worms in my clownfish breeder. I need to know if there is any possibility of an arrow crab attacking a sleeping clownfish. My clowns always sleep on the open sand.

[KLN]

I had an arrow crab kill several fish. Could not figure it out until I caught him at it in the middle of the night.