The Economic Times

In 1998, scientists sent 4 pregnant swordtail fish and 200 babies into space; near the end of the mission, the fish suddenly began swimming in continuous loops

In an unprecedented experiment in 1998, swordtail fish were launched into orbit on the space shuttle Endeavor to explore how life persists without gravity. They initially thrived, swimming well in their custom habitat. However, by the ninth day, they began to exhibit looping movements, a reaction caused by the absence of gravity. Once back on Earth, the fish experienced a brief phase of clumsiness but quickly regained their swimming abilities.