lionfish are awesome. i think its is probably my favorite of all the fish i have had (and that is plenty). like dasnake said, the hardest thing is getting them to take frozen food. but i have found that dropping chunks in the return flow will tempt him, since it drops below the surface and moves around in the current like its alive. I think you need to choose tank mates carefully, i have mine with a grouper who hardly ever lets the lion get live feeders, he's too curious about watching them as he eats them, but its cool to see them corner the feeders with his spikes.