These fish work together by the hundreds of thousands to make waves

Source: Science Daily

In the sports arena, spectators sometimes create a spectacle known as a wave, as successive groups stand up in unison to yell with arms in the air. Now, researchers have shown that small freshwater fish known as sulphur mollies do a similar thing, and for life or death reasons. The collective wave action produced by hundreds of thousands of fish working together helps to protect them from predatory birds.

https://www.sciencedaily.com/releases/2021/12/211222153134.htm