The fearsome appearance of this beast belies its peaceful nature. 

Be careful when go go swimming if you notice what appears to be small waves when there is no wind, or you might find that you never get out again.

A pugnacious creature, the scarlet squid is a highly sought-after commodity by local fishing communities.

30 fantastic monsters to find living in a river. No humanoids, no shapeshifters.

oft eliciting nervous laughter, the Bikini Situation involves not bathing suit bottoms, but rather a problem that arose from the bottom of the Bikini atoll in the Pacific. It is a serious issue for the Pacific Rim Coalition.

Seven Mermaids, some of them living their lives in the deep ocean, others, willingly or otherwise, on the land.

The Liathghorm salmon is prized not only for its flavor, but the unique psychic properties of its flesh.

The Hydra Anemone is a powerful ambush predator found off the hidden Isle of Manjoo. The sorcerous energies there undoubtedly spawning this submarine horror.

The Neo-Soviet marine biomods

The Black Leviathan from the eastern sea is a greater hazard in legend then in fact, as it only infrequently preys upon man. At least, as far as can be told, for many are taken by the sea with no record of their passing.

'Cities in the deep? I've never heard such foolishness. A talking lobster? Rubbish!'

Wild beasts of the imagination — untamed spirits of the quick and unfettered waters of this world. These steeds of the fast-flowing rivers are never to be captured, never to be controlled; to stop is to die — to be stopped is to be turned to droplets which return to the fast-flowing waters. Yet, while free they are things of pure beauty; mystical bringers of the gods' good will.

Before Final Fantasy turned Bahamut into a dragon, it was a fish

-'He's dead, Jim. Drowned, from the looks of it.'

-'Cramps? Swimming too soon after a meal?'

-'No, but something got a meal alright.'

Greentails, sirens, mermaids, merfolk, the creature you think of when you hear these names is a Tangaroa.

I try to avoid them if I can. I see them sometimes herding their flocks of flabby grey creatures into and out of Boston harbor, and it always gives me the chills. Briano tells me that they brought me back to life, but I can't remember it. I can't remember a lot of stuff. He also tells me that I was good friends with one of them once. One of the ones that begs outside of Grand Island Bank for nickels or blood. I can't tell you why I'm uncomfortable around them. They're just fish.

'Ye've ne'er heard of the Shnickels? Ye must 'ave not grown up in yonder country. The Shnickels are pests. Varmints. They move in, and you're done, son.'

-Old Gerald, man in the pub.

Not all of the mermaids and sea sirens are half fish, there are other things that live in the sea

In the strangest parts of The Ocean, the Lojcreltians are born. Beings of weirdness and cosmic balance so profound they can alter reality.

A response to Dragonlordmax's Freetext Friday. Specifically, Exotic Mounts.

Thanks to axlerowes for help fleshing out the details and helping me tie it in further with the rest of the setting.