There are some simple things you can do that will ensure that your fish will swim happily on its way once released. Use a barbless hook, which is easier to remove. If your hooks have barbs, you can flatten them with needle-nose pliers. Bring the fish in quickly rather than pulling it along rocks or letting it flop around in shallow water. Handle the fish as little as possible.
Fish have a protective mucous coating that is easily damaged.
Minimize the amount of time the fish is out of the water. Wet your hands before handling the fish and keep them away from the gills and eyes. If you bring the fish in with a net, make sure the net is both wet and made of a soft material that won t scrape the fish. Take the hook out by bending it back the way that it went in. Keep a pair of forceps in your vest and use them to get a better grip on the hook.