A adoptable I got from  Aurati~Draetlan

This is Prince Kannan, the dragon of the deep. Here we see what he looks like on land and sometimes underwater, but he do indeed have a sea form.

as for his personality, He is more of a warrior type of sea dragon and does get under the skin of Maku; though unknown to both Maku, his brothers and sister, and his friends is that he was raised like differently than the royal family of the Poseidon. Prince Kannan comes from a family of warrior kings from the eastern oceans, Kannan himself train under the supervision of both his mentors and his father Lord Gorran. He respect strength as per tradition of the Nakau Domain thus once you earn that respect, he isn't as bad as he may seem since he is very loyal to his father and his Domain. He does have a sister by the name of Amralth