Koi fish (disambiguation)

Description
The koi fish are a type of fish. They are seen 2 times in the series. The first time was Book 1, Chapter 4: The Warriors of Kyoshi. Aang hitches a ride on the elephant koi, which are massive koi fish. They were eaten by the Unagi, who almost ate Aang as well. The second time we see koi fish was at the North Pole, during the invasion.

Influnce
The koi fish are very important to the storyline. They are the ocean and moon spirits themselves, who gave up their immortality to become a part of the physical world. When Admiral Zhao invades the North Pole, he kills the moon spirit, giving the Fire Nation a complete advantage over the Northern Water Tribe. The other koi fish is swimming all over the pond without the balance of the moon spirit to help it. Princess Yue gives her life to be the moon spirit, which restores balance.

The Spirit World
Without the help of the koi fish, Aang would never have gotten into the Spirit World. He saw the way they used balance, and he had entered the Spirit World.

Only one spirit remembers who the ocean and moon spirits became, the Face Stealer.

Trivia
-The symbol for balance that the koi fish become is the same exact symbol in Shaolin Showdown (on Cartoon Network).