When most people feed their eel's they use a feeding stick of some sort. I purchased one at the LFS. It's just a clear peice of plastic with a point on the end. You skewer whatever your feeding to the end of the stick, and place it in front of the eel. You can also use a peice of rigid tubing, and some have even used plain skewers like the one's for making shishkabobs(sp?).
I don't think that a baby shark would be O.K. in a 55. If your planning on getting/seting up a 180, I would wait until it's up and running. Maybe splash, jim, or novice can give you more input on the shark.