The incredible video below shows a Zebra danio thinking.
Scientists were able to capture the fish's mental reaction as it watched a dot on a screen blinking and moving around. You can see the signals flashing in the brain of the fish, mirroring the movement of the dot, in this video.
Scientists from Japan were able to capture the footage after developing a genetically engineered protein that increases fluorescence in the region of the brain that controls the movement of the fish's eye when it sees something in its environment move around.
A second experiment was conducted using live food (paramecium) with the fish immobilised. While the prey was active, the neural signals could be seen moving around the fish's brain — but they stopped when the prey was motionless.
In a final experiment researchers used live prey once again, but this time the fish was allowed to swim freely about. The team was then able to map the fish's brain activity as it swam towards it.
Why not take out a subscription to Practical Fishkeeping magazine? See our latest subscription offer.