Bobad, that fish is a golden shiner. Golden shiners often have a greenish hue to their upper 3rd. Especially females and immature males which don't take on the more golden spawning coloration. The biggest thing that gives the fish away is the fish has a lateral line that curves toward the venter on the anterior part of the body. Look at the lateral line on your fish. See how it comes out of the gill plate and curves dramatically down? That gives the golden shiner away. Also, the "depth" as you describe it definitely precludes it from being an emerald shiner. You also pointed out the fish is 4" long. It's a young adult golden shiner, but would be an extremely large emerald shiner. Again, another clue it isn't an emerald shiner. I suspect outside of the Great Lakes area, finding emerald shiners for sale at a bait shop would be highly unusual. I suspect about 90% plus of the shiners sold at bait shops are golden shiners.