Amphibia is the eighth Cardian that Alan and Ann send to gather energy for the Doom Tree. Instead of legs, she has a fishlike tail, and her pink hair can extend and constrict enemies and drain their energy. She appeared in Sailor Moon R Episode 8, Raye's Day in the Spotlight.
Alan and Ann summoned Amphibia at the Autumn Festival after raising the audience's energy level when Sarah Howe convinced them to dress up as aliens for the fashion show. Amphibia made everyone fall asleep with a strange powder, but Serena, Amy, Raye, Lita, and Mina escaped the attack. Amphibia used her hair to drain Raye's energy, but the others transformed and stopped her. Amphibia began draining their energy, but Raye transformed into Sailor Mars and stopped her attack with Mars Fire Ignite; however, this was not enough to destroy her. Just then, Moonlight Knight appeared and stopped Amphibia's attack. When she swung her tail and knocked over the music that Raye worked so hard on, Sailor Mars used a new technique, the Mars Firebird Strike, to damage Amphibia and restore the other Sailor Scouts' energy. Sailor Moon then destroyed Amphibia with her scepter.