Epic fish is epic. Whenever I go to SF's museum these are the first fish I go to see.
They swallow air and can bite alligators in half. They lurk around underwater, swimming underneath birds resting on surface and plucking them down with their teeth. Chemically they are nigh invincible, capable of living in fresh and salt water, and near indestructible, with some fish swimming across the Pacific Ocean to Malasia and Indoneshia.
Save for shark species and maybe the barracuda and pike, there has never been a tougher fish made.