Peppermint Shrimp?

[EdsonFOWLR]

I think I might have saw a dead one but it was just a long shrimp sized white chunk of something. The one I can see will come out when food is put in but I don't see any others grabbing chunks of food. Do they kill and eat each other? I also only have 50lbs of rock in the tank, there are hiding spots but you would think food would draw them out a little.