OgreMkV
Father of Earth's Next Emperor
Maybe you could put a flake on a little piece of string... maybe with some kind of small hook...
I've heard of those bobbing glass thingies. I had one in a betta tank... a dragonfly one. He used to sleep on it's tail or wings and bump it around the tank. I don't think it's unrealistic that fish could have 'toys'.
This is what it was like, only mine was an insect.
http://cgi.ebay.com/6-Hand-Blown-Gl...ryZ66791QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
Maybe give these a try?