Juvenile Rock Bass (Ambloplites rupestris). Under 2 inches (5 cm) long, so I would guess it is a young-of-the-year specimen. Clam River (tributary of St. Croix River), Burnett County, WI. Captured in dip-net. Aug. 7, 2016. Shot in photo tank with 90mm macro. (Photo altered, cleaned and adjusted in Photoshop to fix contrast and remove background, suspended sand, etc. Color saturation reduced slightly but otherwise unaltered.)