with a small fishing rod and like a 16 or an 18 (barbless hook) some food at the end make sure as soon as you see go after the food try to set the hook to make sure it goes in his lip. I'm a very active trout and stealhead fisherman and I release all fish that I catch(I do use hooks with barbs because I dont want the fish to get away
) this method isn't harmfull for the fish. For the fish is like getting a shot from a needle almost painless not life threating. The stress comes into play when there out of the water for 2 long of a period of time so when you catch him make sure you get him off of the hook as soon as possible and have a place already picked out for him to go