I got my dwarf zebra to eat a huge frozen silverside the other day for the first time. I just dropped the thawed silverside in the tank close to where the lion is and the current made him look somewhat alive and the lion ate him. After trying this more times it seems to be really effective. When he doesn't eat it the first time I use the tongs to pick it up off the sand bed and drop it again from the top.
I didn't have any luck using the skewers, tongs, etc. I really think these confuse/frighten the fish more than anything. Just my opinion....