This isn't the first time marine habitats have been launched into space, although it is the first high-tech closed water circulatory system to be installed on the space station, courtesy of the Japanese space agency, JAXA. Marine habitats were flown on the shuttle missions STS-47, STS-65, and STS-90, and the AQH builds on experience with supporting fish life in low-Earth orbit. And as you might have guessed, this aquarium isn't in the same league as your household's algae-ridden goldfish bowl.
"In order to keep water quality in good condition for the health of the fish, we had to do many tests on the filtration system, especially the bacteria filter," said Nobuyoshi Fujimoto, associate senior engineer at JAXA's Space Environment Unitization Center. "The special bacteria filter purifies waste materials, such as ammonia, so that we can keep fish for up to 90 days. This capability will make it possible for egg-to-egg breeding aboard station, which means up to three generations may be born in orbit. This would be a first for fish in space."