There are 20 hidden pools in ABZU for you to find and release the fish. If you manage to find the pools in the game, you will unlock the Ecosystem achievement. In this guide, you will find out the location of all the hidden pools in each chapter.
Chapter 1
Hidden pool 1
The first pool is at the bottom of the ocean, so you need to swim through a large hole in the rock and keep near the yellow sand (right) to see the fork. Move forward and click on the "square" button to free the fish.
Hidden pool 2
From the previous location, head back to the large rock and look for a path to the left of the yellow sand. Continue swimming until you see brightly colored plants next to another hole, which is your next pool.
Hidden pool 3
Swim to the rock ledge (which falls) and explore deeper into the ocean floor to find the next pool on the left side.
Hidden pool 4
At the end of the chapter, you will come across a massive rock in the dark. Just swim towards the tower to find another hole and then turn right to find the pool in the center.
Chapter 2
Hidden pool 5
Swim upstream to reach a pink ball-type area. After that, turn right and you will find the first hidden pool of the second chapter.
Hidden pool 6
When you start the chapter, turn left and swim until you find the Meditation Statue and the hidden pool.
Hidden pool 7
Swim to the rock to find the cave entrance. From the entrance, you need to swim higher to find the next hidden pool.
Hidden pool 8
Finally, at the end of the chapter, when you get out of the old location and reach an open area with darkness below, keep sailing to find the Meditation Statue. Follow the ancient ruins where you need to find a vibrant plant to open up another pool.
Chapter 3
Hidden pool 9
See the ancient bridges where you can see two large rocky areas, the lower one hiding a new pool (next to the Meditation Statue).
Hidden pool 10
Swim across the underwater bridge until you reach the land on the right. On the cliff, you will find a hidden pool.
Hidden pool 11
From the previous location, continue your swim to the base of the pillars on the left side to find a hidden pool near the ocean floor.
Hidden pool 12
After opening the exit door, swim towards the trench and continue looking down - the last pool is too close to the chain of open doors.
Chapter 4
Hidden pool 13
From the very beginning, swim towards the seabed and you will find the very first pool of the fourth chapter.
Hidden pool 14
From the previous location, follow the path of the trench towards the destroyed pyramid. After the bones, look around carefully and you will find another pool.
Hidden pool 15
Return to the first pool spot and this time head to where you encountered the bones of yet another wreck. A hidden pool is next to them.
Hidden pool 16
At the end of this chapter, melt down towards the hole with the stalactites. After that, melt higher to find a hole and check out the rocky platform with a hidden pool.
Chapter 6
Hidden pool 17
Swim to the left towards the ladder attached to the chain, then look down to find a hidden pool near the Meditation Statue.
Hidden pool 18
From the very beginning, on the right side you will see a waterfall where you have to swim down to the seabed to find bones, and next to it is a hidden pool.
Hidden pool 19
At the end of this chapter, you will come across a circular location. Turn left to find a new pool near the algae.
Hidden pool 20
From the previous location, swim to the right to follow a narrow path and near the seabed you will find the last hidden pool in the game.
