That glimmer below the waves, could it be treasure? A trick of the light maybe?

Poses:
Gold Mermaid: Harmony by VisNova
Red Mermaid: Spring Chicks by 69step
Backgrounds: Black Room by Wrath (Lighting only) My Second picture in a series of three, and one of the most annoying pictures I've ever really had to work with, though I still like how it came out. For the longest time I farted around with the lighting, trying to get it to look as though they were underwater. When I used a Cyan overlay or transparancy they looked ghostly and ackward, when I didn't use anything, well, they don't look like they're really in the scene, much like they do now. After watching a ton of Hannah the Mermaid videos on youtube I finally decided to leave it as is, even though I still consider it unfinished.

I'm looking for critique on this, helpful hints and suggestions for the lighting.
Much appreciated :)
~Neko