Here is something i posted to someone else a couple of weeks ago who asked the same question
You can get a dwarf lion or any lion to eat frozen. But sometimes it takes a little patience. I got mine to start taking frozen by feeding him a guppie so it put him in to hunt/eat mode. Then I would drop a piece of shrimp directly into the power head current, the shrimp would go flying across the tank and the lion would home in on the motion and snap it up.
After about a week I would float one piece away from power head then another in the direct flow. He finally got to the point where he would wait by the corner of the tank and inhale the dropped in piece. I think he liked the room service . Though every once and a while I would drop it in the power head current and make him work for his meal.
That worked for me. Hope it helps you !!
But after he went to eating frozen he ate chunks of clam , scallop , shelled shrimp and squid. Mine never really cared for frozen krill , i think he was just picky