You dig mythological names? Poseidon is the Greek god of the sea. His Roman equivalent is Neptune. There's also the disgustingly long name Jormungandr, which was a gigantic sea serpent that circled the entire earth (Norse mythology). From my marginal amount of research, it seems that Ebisu is the Shinto god of good fortune, the ocean, and fishing folk.Hah, I need something misleading, but cool at the same time.
I was thinking of mixing up words Infinite, Serpent, Leviathan, Blaze, Inferno, Vast, etc.
If it's female, let's see...Sedna is the Inuit goddess of the ocean. Marah was the Canaanite goddess of the ocean, and Tethys was the Greek titaness of the ocean.
If you prefer celestial names, there's the constellation Aquarius. Cancer is also related to water, but it's a crab, so that's sorta iffy. Mercury has also been associated with water in ancient China, it seems.
There's also El Niño and La Niña.
And that's just water-related.
EDIT: Where IS the trade thread?