Thanks, Theo.
I didn't mention it, but the tilapia IS agressive. It killed two others in a few days when I first started the tank this summer. I read that tilapia would ignore small fish, but this one chewed the fins and killed two little coryadoris cats 2 days after they were introduced last week.
I'm thinking that 4 or 6 bluegill about the same size would make it harder for the tilapia to hurt one. My plan is to remove Tillie if this proves wrong.
