Here is the full list of all 12 ABZU achievements. It takes around 3-4 hours to unlock all of the achievements on Windows.
Release fish from all the hidden pools.
Add all secret shells to your collection.
Discover the polar region.
Breach the water on the back of a blue whale.
Find all the meditation statues.
Perform a flip while riding a creature.
Ride the Great White Shark.
Complete the adventure.
Witness predation while meditating.
Leap from the water.
Discover those that lurk in the abyss.
Burst 15 fish schools in the jetstream.