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.
Breach the water on the back of a blue whale.
Discover the polar region.
Ride the Great White Shark.
Release fish from all the hidden pools.
Find all the meditation statues.
Discover those that lurk in the abyss.
Witness predation while meditating.
Perform a flip while riding a creature.
Complete the adventure.
Burst 15 fish schools in the jetstream.
Leap from the water.