BrookKeeper is right on. You should never let a fish lay in dirt or sand. For the same reason you should never pick up a fish with a rag or a paper towel.
Shiners in particular are very delicate. Their scales will come off in your hand if you handle them roughly or for more than a few seconds. Shiners require extremely fast and delicate handling if they are to survive capture.
PS: rudd also crossed my mind too. They have made it to this side of the pond via reckless introductions. The snout looks just a bit blunter on the rudd than the shiner, though. I believe this is just a big, probably old, golden shiner. Probably a female, based on how round her belly is.