That’s why researchers turned a goldfish into a cyborg

To find out how fish orient themselves in their environment, researchers from Israel implanted a measuring device in the brain of a goldfish. The procedure presented the scientists with major challenges. But their discoveries could be of great importance for the future of animals.

The meter is supposed to measure brain activity when orienting in a new environment. This allowed conclusions to be drawn about the adaptability of fish in a changed environment. Due to pollution and the climate crisis, the habitat of the animals is facing major changes. However, the installation of the measuring device turned out to be difficult.

A goldfish’s brain is only about an inch in diameter. So the scientists at the Ben-Gurion University of the Negev had to be very careful. Since the animal was not allowed to move during the procedure, it was strapped to an operating table. To keep the fish alive during the operation, water and anesthetic were constantly pumped into its mouth.

The operation was performed on the open brain. After the electrodes were anchored in this, they were connected to the recording device. This was packaged in a waterproof case mounted on the fish’s forehead. In order not to hinder the animal’s swimming ability, the enclosure was also covered with a plastic foam.

After the fish had recovered from the major operation, the experiment began. The animal was placed in a tank 70 centimeters long and 20 centimeters wide. It was soon noticed that the navigational cells in the fish’s brains lit up more at the edge of the tank than in the center of the tank.

The scientists conclude from this that fish orient themselves differently than humans. While humans and other mammals ping their location on a mental map, fish seem to rely on some kind of neuron to alert them when they approach an object. Fish can then orient themselves in space using the information about the distances to various obstacles.

The newly acquired knowledge can mainly be used to find out how fish behave when the water becomes cloudy due to pollution. “We modify the environment of many animals, and when you understand how an animal navigates, you know if it is able to cope with the changes that are happening in the world right now,” explains Dr. Adelaide Sibeaux discusses her Israeli colleagues’ research in an interview with the New York Times. Overall, the Oxford University biologist classifies the research project as “pretty amazing.”