European scientists are testing robot “fish” which can detect pollutant at the Northern Spanish port of Gijon on Tuesday, according to Reuters.

This new technology can improve the speed of detecting pollutant significantly, from weeks to seconds. The current method requires people to take sample collection of water to a shore based laboratory, but this robot fish can provide real-time information.

The fish are designed to swim like a real fish fitted with sensors. The fish cost 20 thousand pounds each, and are 1.5 meters long.

The fish can communicate with each other, know where they are. Their battery 8 hours. After battery runs low, they know how to return to base.