China’s space program is making great strides with the Shenzhou-18 mission. This time, three astronauts are sent to the country’s first domestically built space station. Led by former fighter pilots Ye Guangfu, Li Cong, and Li Guangsu, the crew embarks on a six-month mission, which includes conducting experiments and preparing for lunar exploration. In the midst of all this are zebrafish, part of more than 90 scientific experiments. Among them are creating a closed aquatic ecosystem for studying the interactions between fish and algae in space, information that can maybe inform future designs of habitats.