You’ve probably seen the tattoo. Two koi fish, one black and one white, chasing each other’s tails in a perfect circle. It’s a staple of the Avatar: The Last Airbender fandom. But honestly, most people just see them as a cool visual shorthand for Yin and Yang. While that’s technically true, there is a lot more weird, ancient, and honestly heartbreaking stuff going on with Tui and La than most fans realize.
These aren't just fish. They aren't even just spirits. They are the reason the world of Avatar works at all.
The spirits who chose to be mortal
Here is the thing that often gets glossed over: Tui and La didn't have to be in that pond.
Most spirits in this universe—like Koh the Face Stealer or Hei Bai—exist in the Spirit World. They are immortal, ethereal, and generally unreachable by a sharp object. But Tui and La? They made a radical choice "near the beginning" of time. They crossed over. They gave up their immortality to become part of the physical world.
Why? Because they wanted to be the moon and the ocean.
By taking on the forms of two koi fish in the Northern Water Tribe's Spirit Oasis, they became vulnerable. They basically traded god-tier invincibility for a physical body that could be touched, seen, and—as we tragically found out—killed. This wasn't some accidental fall from grace. It was a deliberate sacrifice to maintain the "push and pull" of the planet.
Tui and La: Push and Pull explained (simply)
If you ask Koh, he’ll give you a whole cryptic speech about an "eternal dance." But basically, it comes down to the names themselves.
- Tui (推): Means "push." She is the Moon Spirit, the white fish with the black spot.
- La (拉): Means "pull." He is the Ocean Spirit, the black fish with the white spot.
In the real world, we know the moon’s gravity pulls the tides. In Avatar lore, it’s a bit more of a collaborative effort. Tui provides the power—the raw energy that waterbenders tap into. La provides the actual substance, the ocean itself. They are the original waterbenders. Everything Katara or Pakku does is essentially a cheap imitation of what these two fish do every second of every day.
When Admiral Zhao killed Tui, he didn't just turn the sky red. He literally severed the source of waterbending. It’s like unplugging a lamp; the lamp (the bender) is fine, but there’s no juice coming through the wire.
What happened to the "Original" Tui?
There’s a common misconception that Princess Yue is Tui now. It’s a bit more nuanced than that.
When Yue was a baby, she was basically born dead. Her father, Chief Arnook, took her to the pond and begged the spirits for help. Tui touched her, turning her hair white and giving her a spark of its own life force. When Zhao killed the physical koi form of Tui, the spirit was gone. Dead.
Yue didn't just "replace" her; she returned the life force that was loaned to her. In doing so, she became the Moon Spirit. But that original consciousness that had lived in the pond for thousands of years? That’s effectively gone. Yue is a new iteration. It’s a heavy concept for a "kids' show," but Avatar never really pulled its punches.
The Wrath of La
We have to talk about "Koizilla."
Most of the time, we see La as the "pull"—the calmer, reactive half. But when his partner was killed, La went absolutely nuclear. He didn't just sit in the pond and cry. He merged with Aang (who was in the Avatar State) to become a massive, glowing water titan.
This is a rare moment where we see a spirit interact with the physical world with that much raw violence. La wasn't just defending the city; he was venting thousands of years of grief in about ten minutes. Interestingly, La didn't need the Avatar to exist, but the Avatar provided a bridge that allowed him to manifest that level of physical power.
Once the balance was restored by Yue, La went back to being a fish. Just... a very lonely fish for a moment until the new Tui took her place.
Why this still matters for fans
The story of Tui and La is the ultimate lesson in the show’s core theme: balance.
It’s not just about "good vs. evil." It’s about the fact that you cannot have a moon without an ocean, and you cannot have a "push" without a "pull." If you destroy one, the other becomes a monster. Zhao’s mistake wasn't just being a jerk; it was fundamentally misunderstanding how the universe is wired. He thought he could win by deleting a piece of the puzzle, not realizing the whole thing would collapse on his head.
Actionable insights for lore buffs
If you're looking to dive deeper into the spiritual mechanics of the Avatar world, keep these details in mind for your next rewatch or Tabletop RPG session:
- Check the eyes: Notice how Tui and La always circle each other. This is the "Taijitu" in motion. If they stop, the world stops.
- The Kuruk connection: In the live-action adaptation and expanded lore, we learn more about why spirits like these are so wary of humans. Avatar Kuruk actually hunted dark spirits, which complicated the relationship between the human world and the oasis.
- Bending limits: Remember that waterbending is the only art directly tied to a physical, killable spirit. Firebenders have the sun (a massive ball of gas), and Earth/Air benders have the planet itself. Waterbenders are uniquely vulnerable because their "gods" live in a backyard pond.
Pay attention to the color grading in the "Siege of the North" episodes. When the moon goes dark, the world doesn't just lose light—it loses its "soul." That’s the real legacy of Tui and La. They aren't just characters; they are the environment itself.