Fish of the species Erismatopterus levatus swam in unison, as modern fish do today.
These 259 baby fish were seen by Arizona researchers, who reported in it in the journal Proceedings of the Royal Society B. They thought that the fish probably originated from America's Green River Formation, where fish between "53 million and 48 million years ago" are thought to exist.
"’ We found traces of two rules for social interaction similar to those used by extant fishes: repulsion from close individuals and attraction towards neighbours at a distance,’ the researchers wrote in their study.”
This synchronized swimming might have saved the fish from a predator, although it did not prevent them from becoming a fossil for us to see.
They might have well perished in the flood of Noah’s Time, as the research shows that “have been cut short by an underwater avalanche of sand.“