Threadfin Butterfly Feeding

[intarsiabox]

I've had a threadfin butterfly for a couple of weeks now and it seems to have trouble eating anything but frozen brine shrimp. He tries to eat Mysis and soft pellet food but after trying to eat it for a second or two he spits it out. Nori sheets are also ignored. He's also turned into a very lazy fish and will only eat the brine shrimp if I put it in front of his nose. If it sinks too far he'll watch it float away and then look back up to the turkey baster for the next one to drop out. The first week he swam all over the tank for the food. Anyway, in the 10 or so years I've been keeping SW fish I've never wanted to use flake food but I'm thinking the butterfly would have an easier time eating it. Does anyone else successfully feed their butterflies flake foods? What brand? Thx