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