Head-Over-Heels (do crabs have heels?)

Recently I received more pets for my birthday. If you frequent this site you've probably seen pictures if my aquarium and have heard about how I am disgusted/intrigued by crabs. One of my new pets is a fiddler crab and he's a big one.
So after the new pets were acclimated to the temperature of my tank, I removed them from the bags they were floating in, fed them, and quickly duct-taped all of the holes in the top of the tank (You don't want that crab climbing out. Also, one of the new fish was a butterfly fish which are supposed to fly out if the water).
From day one I noticed that the butterfly fish wasn't active, but some fish take a while for them to get settled in, so I just waited, expecting it to get better.
It didn't.
BUT, my new crab is literally head-over-heels for this dead fish. If you didn't know, crabs each dead stuff. They'll latch onto something with all six legs and then use their small pincers to feed themselves. It's a bit unclear due to the tank water, but I think you can make it out.
Check out the two pics of the crab having breakfast and then there is one of the new swordfish that looks like he will be traumatized from watching for quite some time.