From Dragon Ball Encyclopedia, the ''Dragon Ball'' wiki
Aqua (アークア, Ākua; FUNimation "Arqua") is a martial artist.
Aqua is a Fish-like humanoid alien.
Dragon Ball Z
Aqua was formerly from the Eastern Galaxy. He was matched against Son Goku in the third round of the Next World Tournament where he began with a rough start. Shortly into the match, Aqua transformed the Next World Arena into a watery environment, giving him somewhat of an advantage in the battle. With his strategy combining the Solar Flare technique and the Kamehameha technique, however, Goku was able to launch Aqua out of the arena and emerge victorious.
After his defeat, Aqua was scolded by East Kaio for allegedly ruining her reputation and was ordered to run 1000 laps around Grand Kaio's Palace. Goku confessed that he had been impressed with Aqua's abilities and proposed that they one day have a rematch, imposing some joy in the usually melancholy Aqua until East Kaio yelled at him once again.
Pikkon easily defeated Arqua in the semifinals in Dragon Ball Z: Fusion Reborn.
He is named Arqua in Dragon Ball Z: Buu's Fury.
- Dokodemo Mizu ni Kaeteshimau Nōryoku – An ability where he momentarily generated water that enveloped the area. He used this in his match against Goku at the Next World Tournament to change the entire arena into a giant fish tank. Aqua was unskilled on land, but in the water utilized unrecognizable speed and power, giving even Goku a tough fight.