German researchers on Thursday launched a rocket carrying 72 small fish on a brief space flight to study motion sickness.
The cichlids were in an unmanned rocket that blasted off from a launch pad in northern Sweden, said Professor Reinhard Hilbig, who was in charge of the project.
The thumbnail-sized fish were filmed as they swam around weightlessly in small aquariums during the 10-minute space flight.
The German team will now study the video to see if some of the fish swam in circles because that is what fish do when they experience motion sickness, said Hilberg, of the Zoological Institute at the University of Stuttgart.
He said the scientists hope the experiment can help shed light on why some people experience motion sickness while others do not because the mechanisms involved are similar for both fish and humans.
Hilbig said the fish landed safely and appeared to be in good condition.
"They were very happy, I think they want to have another flight," he said.
Cichlids were picked for the experiment because they are sturdy fish who were deemed to have good chances to survive the stress of a space flight.
"Goldfish are a little bit fat and messy, while the cichlid fish is a well-trained, sporty fish with muscles," he said.