Smaller chunks maybe? I remember trying to feed banana a few years ago after reading this thread,
http://canreef.com/vbulletin/showthread.php?t=4695&
... but my fish sort of just looked at me funny as if I was some strange alien. Well, I mean, more so than usual.
Although after re-reading that thread and seeing Emilyb's comments about her CBB liking banana, I'm tempted to try again, just to see if my CBB will try it too.