It looks like fish, it moves like fish, but it’s a robot

The world’s first, fully-autonomous display of free-swimming robot fish was launched in October 2005 to global acclaim at the London Aquarium.
fish4 fish6
The robot fish are capable of swimming under their own control for hours at a time in an ordinary tank as they contain all their own batteries, micro-controllers and sensors.

The robot fish were commissioned by the London Aquarium and produced in collaboration with the University of Essex.

The development overtook several American universities and Japanese companies along the way – taking less than three years to go from first concept to first public demonstration

An earlier generation that swims like a shark:
shark fish8

In the final versions The Robot Studio concentrated on producing visually striking outer bodies – the fins, head and the scaly skin.

The design of the fins on the robot fish turns out to be crucial for efficient swimming.

The same is true of the scaly skin, which must be good-looking, have low-water resistance, be made of materials that can survive continuous immersion, be very light-weight and highly flexible.