Didn't we ID this fish as a blackbanded darter in another thread?
All the bladder stuff still applies
Looked like a dusky at first glance, but... no, subtle differences. My dusky is pinkish on the bottom, and doesn't have the mottling on top.
And, technically speaking, the only fish that floats is a dead one, though dead darters don't tend to float.
All this bladder talk has me headed to the restroom.