Aquarius is an ancient female Chao and patron of the Eusebes Shrine of Meropis. As such, she is revered by the people of the city, including King Puff and Queen Angelica. Following the natural Chao life cycle, she entered a cocoon state under the care of Coral the Betta, but for unknown reasons did not emerge normally. This delay caused additional turmoil while the city was facing The Shattered World Crisis, and led to Coral's abilities as a priestess being questioned.
At some point in the history of Meropis' people, Aquarius taught them mystical rites that allowed for the creation of a mystical shield that would protect their city from all threats. Aquarius was honored for her deeds, and the Eusebes Shrine was erected near the city in the midst of a Chao Garden, where Aquarius and her kind could live in peace while a priestess maintained the shield over Meropis. (StH: #262)
As all Chao do, Aquarius entered a cocoon state to renew herself shorty after The Shattered World Crisis began. Prior to this, she and priestess Coral the Betta were contacted by the spirit of Tikal, who informed them that a group of heroes would soon arrive. Aquarius subsequently entered a cocoon, but failed to emerge at the expected time. This occurrence created doubt in the minds of Meropis' people as to Coral's competence as priestess, and King Puff and Queen Angelica revoked her title. To make matters worse, the stress on Coral led to the city's shield falling, allowing Dark Gaia's Minions to swarm Meropis. A desperate Coral did her best to restore the shield, wishing that Aquarius would emerge and help her perform the rites, but was forced to continue alone. (StH: #259, #260, #261, #262)
When the rites fail to restore the city's shield, Coral begins losing hope again. She begs the spirits for help and receives it in the form of Tikal. Tikal reveals that Aquarius is actually still alive, but has been reborn as an immortal Angel Chao. Overjoyed to see Aquarius alive, Coral regains her confidence and has Pearly and Tikal help her and Aquarius perform the Mystic Melody and restore the city's shield and destroy the monster's attacking it. (StH: #263)
Aquarius is a white Chao with dark blue and blue-green markings, with a white halo that floats above its head. She has long ears with dark blue tips separated from her white head by blue-green stripes, and wears a seashell necklace.