Fish Survive 43 Days on China's Space Station. It's a New Record

Zebrafish that accompanied astronauts on the Shenzhou-18 mission to China's space station last year have set a record after surviving 43 days in space.

Sun Yonghua, a researcher at the Institute of Hydrobiology of the Chinese Academy of Sciences in the central city of Wuhan, said the fish's longevity in space "represents a significant breakthrough in the cultivation of vertebrates and aquatic plants in space," the official China Daily newspaper reported today.

In April, two male and two female zebrafish, along with aquatic plants from the institute, were sent on the Shenzhou-18 manned space mission to China's Tiangong space station.

At the station, astronauts collected water samples and fed the zebrafish, observing “abnormal behaviors” such as swimming upside down or twisting and turning in the microgravity environment, Sun said.

Scientists and researchers at the institute have been using recovered water samples and other samples from closed aquatic ecosystems to analyze the impact of the space environment on the growth, development and behavior of vertebrates.

The genome similarity between zebrafish and humans is 80 percent, making them an important species for research into human diseases.

According to Sun, more than 500 laboratories across the country are conducting research and studies on zebrafish and other related species.

Expert Wang Gaohong, also a researcher at the institute, pointed out that, like humans, fish also face adaptability problems when surviving in a space environment.

"The researchers worked to create an ecosystem where aquatic plants produce oxygen through photosynthesis to provide respiration for the fish, and fish waste provides nutrients for the aquatic plants," he added.

Sun explained that fish food in space "is like toothpaste. You squeeze a little bit into the water for the zebrafish to eat, but try not to give them too much, as it can degrade the water quality."

Zebrafish, also known as zebra danio, are a type of elongated freshwater fish related to carp and barbel.

To date, 181 scientific and technological projects have been implemented at Tiangong, ranging from biological experiments to the development of new technologies, Chinese space program officials said recently.

Tiangong, which will operate for about 10 years, could soon become the world’s only space station if the International Space Station, a US-led initiative that China is barred from accessing due to its military ties to its space programme, is retired soon as planned.

China has invested heavily in its space programme and has successfully landed the Chang’e 4 probe on the far side of the moon – a first – and another probe on Mars, becoming the third country – after the United States and the former Soviet Union – to do so.