Red and/or bleeding fins are an indication the fish has become stressed and will be tougher to revive/release. This is most common in summer when water temps are high. Its best to keep out of water time to a minimum with stressed fish, better yet a water release with no out of water time! Muskie may look big and mean but they are a very delicate animal, and a valuable resourse, a 20 pound Kawartha Muskie is likely 15 years old, not easily replaced.