The Space Aquaculture Project at Okayama University of Science is an ambitious research initiative aimed at cultivating fish and crustaceans on the Moon and Mars, which are expected to serve as food production bases for future space exploration. The project ultimately seeks to improve the quality of life of astronauts through better food options in space.
However, transporting fully grown fish into space would be inefficient. In reality, fish would need to be brought into space as juveniles, larvae, or eggs. Juvenile fish and larvae are vulnerable to external stimuli, and many questions remain as to whether they can properly feed under microgravity conditions. This uncertainty was the direct motivation for the present experiment.
The research group includes Associate Professor Toshimasa Yamamoto and Associate Professor Ryusuke Tadokoro of the Faculty of Life Science; Visiting Professor Seiichi Tsumura of the Next-Generation Aquaculture Center; and Professor Syou Maki of the Institute of Frontier Science and Technology, who also serves as head of the Distance Education Course.
Methods for creating microgravity on Earth include parabolic flight and drop towers. However, none of these methods are suitable for long-duration experiments. The group also tested a magnetic-force-based method that had been used at another university, but this approach did not work well either. The researchers therefore decided to try using a clinostat.
A clinostat is a device that creates a simulated microgravity environment by rotating an object around two perpendicular axes, thereby canceling out the effects of gravity. However, while this can produce a simulated microgravity state for objects fixed relative to the rotation axes, it is not effective for samples such as fish, which can freely change their posture in water. With the relatively slow rotation speed of a conventional clinostat, around 20 rpm, fish quickly regain their posture in the water and move toward the center of rotation, where the load from centrifugal rotation is smaller. In other words, it was clear that a conventional clinostat could not make fish experience simulated microgravity.
The group therefore decided to develop a new clinostat that rotates so rapidly that fish have no time to regain their posture, and commissioned a specialized manufacturer to build it (Advanced Engineering Services Co., Ltd.). In addition to the modified clinostat itself, the researchers developed by hand the container for holding the fish, camera fixtures, and protective containers capable of withstanding high-speed rotation. This work was made possible with the cooperation of Kanji Kameyama, an engineer at the university’s Science Dream Lab, also known as the Design and Manufacturing Center.
After the device was completed, the group repeated a process of trial and error and finally succeeded in recording video footage of juvenile shrimp feeding. They then conducted genetic analysis of the shrimp, including Gene Ontology analysis, and found several results that appeared to be caused by exposure to a microgravity environment.
Because each experiment could accommodate only one to three shrimp at most, the researchers felt it was necessary to increase the number of experimental samples. They therefore conducted supplementary experiments using Artemia, another type of crustacean, to support the results obtained from the shrimp experiments. Artemia are only about 1 mm long at most and grow very quickly, allowing the researchers to place 10 individuals in a container at once and expose them to microgravity for four days. The group also conducted experiments using Tetraselmis , which serves as food for Artemia, and confirmed that Artemia continued to feed on Tetraselmis even under microgravity.
All of these experiments used Third Water developed by Okayama University of Science. This water is also known as “ Koteki-Kankyo-Sui ” in Japanese. Hence, it is expressed as “ Koteki water ” in the paper. Because the use of Third Water is considered the most rational and productive approach for realizing space aquaculture, experiments were conducted using the optimal conditions for this water.
The paper summarizing this research was published in June 2026 in the international academic journal Microgravity Science and Technology . The title of the paper is “In Situ Observation of Shrimp Feeding Process Under Microgravity Environment.” This is the first academic paper published since Okayama University of Science began its Space Aquaculture Project.
The group is currently developing an aquaculture tank with the same water volume as the tank envisioned for installation on the International Space Station. Using Third Water, the researchers are attempting to realize a completely closed recirculating aquaculture system and to maintain aquaculture for at least 100 days without any water exchange. They are also developing various ideas, including an automatic feeding device that can be controlled remotely and plan to incorporate AI functions into technologies for identifying individual organisms.
In addition, the researchers are working on cultivating Artemia as feed for fish larvae, as well as Tetraselmis , which serves as feed for Artemia. The entire Okayama University of Science team is working together, step by step, toward realizing the dream of space aquaculture.
Microgravity Science and Technology