How do you get fish to play a video game? Well, you have to make it immersive, of course.

Researchers at Princeton University did just that in an effort to understand why fish hang out in groups.

They created an in-tank video game system for some hungry bluegill sunfish. The researchers projected simulated prey onto one wall of the enclosure and then measured if and how the bluegill interacted with their faux foes.

The results showed that, not surprisingly, there is safety in numbers. The gamers were less interested in prey that grouped together and least interested in groups that moved in sync.

The game environment allowed researchers to see exactly which individual and group behaviors interested the predators in a way that observation in the wild doesn’t permit. After all, when you’re observing predator/prey behavior, it’s difficult to have your subjects back up and try again.

The researchers set the prey projections up so the game didn’t become predictable and actually became harder the more the fish played.

“In any computer game if you have one type of enemy it’s easy to learn,” said Princeton’s Dr. Iain Couzin, who led the study. “It would be fascinating to understand whether the fish learned to play the game better over time.”

Image courtesy Wikimedia; video courtesy Princeton University