Congrats!
I would suggest keeping with krill for about a week. With one or two days of no feeding, to make sure your pike gets a chance to digest and flush the system...It'll also make him hungry for the next time you feed him.
Next I'd get some hikari pellets, put some in a small tupperware container and place the frozen krill on top of the pellets. Let the krill thaw, making sure that the pellets have soaked up some of the krill juice. When you feed, put a couple pieces of krill in the tank and then put a couple pellets. Feed slowly, one or two pieces at a time. The fish might not eat the pellets at first, but dont get frustrated...Sooner or later they will come around to them.
"Dump Feeding" will only put too much food on the substrate, and not enough in your fishes belly.
Good luck and I'm glad your pike is eating!