A newer addition to the physics-based puzzle games, Jellyflop! is wins with a combination of entertaining gameplay, adorable animation and fun audio.
iPhone and iPad apps tagged "underwater theme."
Pudge is a Challenge to Master
Combine an adorable animated puffer fish with a snappy soundtrack and the premise of a simple arcade game and you have Pudge. Similar to iCopter, but with far better graphics, Pudge utilizes one-touch controls to move a puffer fish through an underwater cave, avoiding obstacles along the way.