If you do this correctly you will not need the pliers. If the fish has the strength to wiggle its tail, let it kick out of your hand and swim, do not hold it back. If you keep a fish to eat, make sure that it is silver and fresh. Do not keep a dark fish as it is probably too near to spawning and the meat will not make good table fare. Coho like just about any terminal tackle that is properly presented.
Presentation is everything.
And to have some fun with the colors they should be silver, blue or green. I love using the flyrod in a weight 8 or 9 or a light spinning rod and reel filled with 12-pound test and a jig as terminal tackle. If you find a pool or run where you can see the fish because the water is very clear and not that deep, your terminal tackle choice should be a lure such as the Lure Jensen Krocodile or a light thin spoon weighed if needed, with split shot. Use something thin that glides through the water and is designed to represent small fish that the Coho think are a threat to their spawning reds or area. The spinner blades cause it to be retrieved slowly, letting the fish have a good look at it and thereby making a decision to strike.