At a research station tucked away near the beaches of Palavas-les-Flots in southern France, hundreds of tiny sea bass circle a tank. They’re not aware of it but they’re part of a daring experiment that may one day change life beyond Earth. If all goes to plan, their descendants will be among the first animals raised on the Moon, providing fresh food for astronauts on long missions far from home. Extra-terrestrials, you might say.

The project, called Lunar Hatch, is led by Dr. Cyrille Przybyla of the French National Institute for Ocean Science (Ifremer). It aims to answer a fundamental question for future space explorers: how do you reliably produce fresh, nutritious food on the Moon?

“Fish is an excellent source of protein because it is the animal organism that we digest the best,” Przybyla told The Guardian. “It has omega 3 and important B vitamins that will be needed for astronauts in space to maintain muscle mass.”

A Bold Experiment in Space Aquaculture

The plan is as ambitious as it sounds. Scientists will fertilize sea bass eggs on Earth, then blast them into space aboard a cargo spacecraft. The journey, lasting between four and eight days, coincides perfectly with the eggs’ incubation period. Ideally, they would hatch either en route or shortly after arrival at a lunar base.

The fish would grow in tanks filled with water extracted from ice found at the Moon’s poles, regions permanently shielded from sunlight. These tanks would form part of a closed-loop aquaculture system, where every waste product becomes a resource.

“We’ve done all the possible simulations we can do on the ground so the goal now is to have a space mission to verify that data,” Przybyla said.

Once in operation, the system would mimic Integrated Multi-Trophic Aquaculture (IMTA), an Earth-based method theorized in 2004. This approach combines different marine species to recycle nutrients. Wastewater from the fish would feed microalgae, which in turn would nourish filter-feeders like bivalves and zooplankton. Shrimps and worms would process leftover waste—and also serve as food for the sea bass.

“The aim of Lunar Hatch is to have no waste,” Przybyla emphasized. “Everything is recycled through an aquaculture system that would have to be autonomous for four to five months.”

The goal: two fresh portions of sea bass per week for a seven-person crew, over a 16-week mission. To achieve this, around 200 fish would be needed.

Preparing for Launch, and Life on the Moon

The idea of sending animals into space isn’t new. In 1973, tiny mummichogs—hardy fish from coastal North America—traveled aboard an Apollo mission. Guppies swam in the Soviet Union’s Salyut space lab in 1976. More recently, zebrafish were sent to the International Space Station to study muscle loss in microgravity.

But Lunar Hatch is different: it aims to actually farm the fish in space.

Researchers have already tackled critical questions. Would the eggs survive the violent vibrations of launch? Would cosmic radiation or changes in gravity damage their DNA? Early tests suggest they will. Using equipment from the University of Montpellier’s Space Centre, scientists simulated the intense shaking of a Russian Soyuz rocket. Fertilized eggs at different stages of development withstood the stress.

The project has been years in the making. Przybyla first proposed it in 2016 when the European Space Agency (ESA) sought ideas for a “Moon Village.” Funding arrived in 2018 from France’s national space agency (CNES), and Lunar Hatch is now among 100 projects shortlisted for ESA’s future Argonaut lander missions starting in 2034. These robotic cargo ships could deliver up to 1.8 tons of equipment to the lunar surface—including a small but precious cargo of sea bass eggs.

If successful, Lunar Hatch could become a model for sustainable life-support systems, both in space and on Earth.

In a world facing growing challenges of food security, what begins as a solution for distant astronauts might soon ripple back to communities isolated by geography, climate change, or conflict.

For now, the fish at Palavas-les-Flots continue their slow, spiraling dance, unaware that their offspring may one day help humanity take its next giant leap.