I don't think it is a bluegill; it seems too narrow whereas a bluegill would have more of a pan shape.

I wondered if it might be a LMB, but I don't think so either.

My guess would be a minnow of some type.

Let's see what the consensus is...

Excerpt from Robert Crais' "The Monkey's Raincoat:"
"She took another microscopic bite of her sandwich, then pushed it away. Maybe she absorbed nutrients from her surroundings."