Stowfish

Stowfish is a fish that appears in The Legend of Zelda: Phantom Hourglass. You can't catch it like a regular fish. It is sometimes attached to another fish, and if you catch a fish that has a Stowfish attached to it, it will count as a Stowfish catch. When you show a Stowfish to the Old Wayfarer he will give you a random ship part.