From Dragon Ball Encyclopedia, the ''Dragon Ball'' wiki
The Kanassans (カナッサ星人, Kanassa-seijin) are a race from Planet Kanassa.
The Kanassans are Fish-like aliens.
The Kanassan warriors are shown to be extremely brave. Despite knowing from their visions that they will be destroyed, they put up an honorable fight against Bardock and his team. They are shown to be very honorable, a good example being the conversation between Demetrious and the unnamed commander, in which after Demetrious draws blood, the commander states that "you have done well my friend... I will meet you at the door.", implying that he has served his honorable duty and now must pass on to the next world.
Kanassans appear to talk telepathically to one another, as when Demetrious is seen talking his mouth does not move. They also appear to have been able to harness Ki energy, another reason why they had put up such a hard struggle against the World Trade Organization's forces.
The Kanassans appeared in Dragon Ball Z: Bardock: The Father of Goku. They were said to possess psychic abilities, including the ability to read minds and see into the future. Freeza therefore ordered their extermination out of paranoia that they could become a threat to him, or to simply use the planet's unique energy for himself. They were wiped out by Bardock's team, who turned into Great Apes during a full moon.
Bardock and his crew were assigned by Freeza to exterminate all lifeforms on Planet Kanassa. Afterward, a remaining survivor named Toolo caught Bardock off-guard and gave him the "gift" to see the future. The Kanassan believed that this would give him the ability to see the destruction of own homeworld, Planet Vegeta, and the entire Saiyan race with it at the hands of Freeza. Tora then disposed of the weakened Toolo.
Dragon Ball Z
A Kanassan appeared in "Warriors of the Dead" during the Great Saiyaman Saga where he was training on Grand Kaio's World.
- Full Power Energy Blast Volley – A group of Kanassans use this technique against Planet Elite Force while in their Great Ape forms.
- Full Power Energy Wave – A group of Kanassans use this technique against the Planet Elite Force while in their Great Ape forms.