We all know about fish schools, but what exactly are they learning all day? Young fish learn in very much the same ways that human children do. Researchers presented damselfish with the scent of a predator along with the scent of a damselfish alarm cue. Later, when the damselfish met the actual predator, they understood the danger and protected themselves. It's similar to when a kid sees a bully take someone's lunch money and knows not to go near him.
Fish tend to join large schools in order to protect themselves and make it easier to find food. In a study of angelfish, researchers let young fish choose between two schools and found that the fish were able to easily estimate which was the larger school. They also let the fish choose between a group of two and a group of three and noted that fish could count to three in order to determine which group was larger.
Other studies have found that fish use tools, have impressive long-term memories, and have sophisticated social structures. Some male fish even woo potential partners by singing to them. So the next time you sit down to eat sushi, remember that you could possibly be eating the ocean's Justin Bieber—and choose vegetarian versions instead.
Written by Michelle Sherrow