It may seem like something out of a science fiction film, but soon robotic fish could be patrolling the seas around Britain!
The 'robofish' will be able to detect pollution in the water and send the information back to experts.
They can communicate to each other and swim around without needing to be controlled by humans.
Scientists hope the fish will be able to spot dangerous chemicals and help stop damage to the environment.
A shoal of 'robofish' are set to be released off northern Spain as part of a three-year project.
The team who makes them says the fish could be used in rivers, lakes and seas across the world, including Britain, to detect pollution.
Each robot costs £20,000 to make and measures 1.5m in length, which is roughly the size of a seal.