Lol... I can see this game isn't gonna kick off at all if it doesn't get a better community. You're all taking it WAY out of context. e.g Does a frog turn into a tadpole when submerged? No. Is a frog a fantasy creature? No. Is this a Fantasy Game? Yes
Take a look at WoW for example.. when Night Elves die they turn into a wisp form, and they have more speed than other races in wisp form. Turning Nolthrirs into a sort of Mermaid-esque creature when they are underwater could give them the upper hand at swimming over other races, which is obviously what they should have anyway.