Sharks? No Conway Bowman and others have proven that not only can you catch sharks on flies, you have a lot of fun doing so. Muskies? No, the fish of 10,000 casts might be the fish of 20,000 casts when you fly fish, but it can be done. Halibut? I've actually caught halibut in Alaska by dropping a heavy fly into water about 40 feet deep, and bouncing it along the rocks. Was that classic fly fishing? Well, no... but I was using fly tackle.