Um, no.
(1) Mythical Zoans have a SPECIFIC myth creature. Phoenix, Buddha, 9-tail Fox, Yamata no Orochi, etc... "Dragon" is too generic.
(2) Fish are not dragons. Mythology aside, base DF has to match model.
Phoenix is a bird.
Buddha is a human.
9-tail Fox is a canid (also called "Inu").
Yamata no Orochi is a snake.
The only "violation" we have is from a video game (Oda designed I think) where we have Bat Bat no Mi, Model: Vampire, where vampires turn into bats or something. So it could be something like
Uo Uo no Mi: Shenlong model or something.
I wouldn't be surprised if he is something like "Leviathan", but he does seem to be more eastern oriented.