There's a new breed of fish swimming inside the London Aquarium. It has the speed of a tuna, the acceleration of a northern pike and the maneuverability of an eel. Sounds like a great fish to catch, right? Well, sharpen those hooks, because this guy is more machine than marine. "Our robotic fish are very entertaining," said Foster Archer, director of the aquarium. The aquatic automatons have built-in, sensor-based controls that allow them to swim freely and react to their environment. And even though rods and reels will have to be left at the door, Archer expects the robo-fish to be "very popular with vistors."