Unknown fish? Amphibian? Leaf?

I'm not sure what this thing was, or even 100% positive it was alive. It seemed to be moving faster than the current, but only slightly. It kind of looks like a tiny catfish, but I don't know of any small species of catfish, and the water is too shallow for any larger fish.
Unfortunately, I lost it after getting distracted by all the toads, as well as a rare sighting of a beaver (which, at the time, I thought was a river otter, which would've been even more unusual for the area), so I didn't get any better shots of it.