http://i.imgur.com/Z0LSSpY.png

There's a lot you can do with this deck. You can swarm the field and XYZ your heart out or Synchro using the Deep Sea Divas. Or you can use Dragoons to let your Level 3 and lowers attack directly. Another possibility is to fill your field, torrential tribute or Dark Hole, then use Torrential Reborn to repopulate the field. With a well placed Heavy Storm, this could even be an OTK.

XYZs:
Leviair the Sea Dragon
Number 17: Leviathan Dragon
Number 32: Shark Drake

Synchro:
Sea Dragon Lord Gishilnodon
Gungnir, Dragon of the Ice Barrier

Creatures:
Poseidra, the Atlantean Dragon x2
Warrior of Atlantis x2
Atlantean Dragoons x3
Atlantean Attack Squad x3
Atlantean Marksman x3
Legendary Atlantean Tradion x3
Deep Sea Diva x3
Atlantean Heavy Infantry x3

Spells:
A Legendary Ocean x2
Call of the Atlanteans x3
Dark Hole
Forbidden Lance x2

Traps:
Aegis of the Ocean Dragon Lord x3
Poseidon Wave x3
Torrential Tribute x2
Torrential Reborn x2