A team of Japanese researchers has recently managed to have a look at the thought process of a zebrafish larva, all with the help of a sensitive fluorescent marker, which allowed them to observe the ways in which neural signals travel inside the bodies of the tiny creature.
Thus, the fish larva was simply allowed to swim freely and go about its business, while the scientists who embarked on this project kept themselves entertained by watching it think, Live Science
At one point, they even added a paramecium in the zebrafish larva's environment and watched it hunt it.
Commenting on this scientific achievement, Florian Engert, a molecular and cell biologist currently working with the Harvard University, argued as follows:
“It's a breakthrough. No one else can look at neuronal activity with fluorescence microscopy in a freely swimming zebrafish larva with such good resolution.”