I'm just wondering if anypony wants to tell me what they know about seaponies. If anypony has any theories they want to share, tell us.

730183
Well here's some head canon I have on sea ponies.

There are three different types of seaponies, just as there are land ponies.

First is the hippocamps, which is literally a horse with a fish tail and fins for hooves, and are basically the earth ponies of the sea.

Next are octoponies are like cecaelia which in mythology is a creature with the upper body of a human or elf and the lower torso of a squid or octopus and the same is true for the octoponies as they have the front quarters of a pony and the rear quarters of either a squid or octopus. They can travel on land short distances by use of their tentacles/
Just like octopi and squid, octoponies are known for their intelligence, proving to be crafty and genius with puzzles and riddles of nearly any sort. They also have keen eyesight just like their octopi counterparts, making them fearsome in battle and as predators. Just like octopi they have also been known to kill sharks with only their tentacles thus making the only ones who would challenge them either brave or stupid.
They also come with the natural ability to camouflage themselves just like any octopus under the ocean. They can also compact their bodies to fit into tight spaces and crevices that other creatures of the sea cannot.
They live in all parts of the ocean, preferring cold, dark places usually.
If you're wondering why I called the most attention to this particular thing it's because I love octopi and squids as they are two of my favorite sea animals.
The octoponies serve a similar function to unicorns in the undersea kingdoms. They're adept at magic and their tentacles allow them to grasp and manipulate objects far easier than the hippocamp style of sea pony.

Finally we have the winged hippocamps or flying seaponies which as you may guess are like the pegasi. They are the fastest of swimmers out the sea pony species and can even glide outside water just like flying fish.

730203
Do you have a picture of winged hippocamps?

730215
Well there's this I found on deviantart

730228 Hmm... interesting

730183
Well, I know that the sea ponies (unsure when) gave Megan (G1) a shel that she later on in "the ghost at the paradise mansion/estate" (G1, year seven, 1986, episode 11-14) use to call upon the sea ponies, that make it possible for them to travel under the water to save their bird friend, Luna's, grandfather.