Depending on how you weigh a fish can determine if it will harm the fish or not. Traditionally fish scales worked with a hook placed under the fish's gill plate to read the weight. The problem with this is if the fish flops around the hook can damage the fish’s gills. Luckily, advancements in scale design resulted in fish lip grippers. This handy tool clamps onto the upper lip of a fish securing it from flopping around. You still get an accurate weight and the fish will swim off unharmed.