Composition

I wanted the overall composition to be an overlaid triptych of organic shapes that resembled schools of some kind of sea life flocking through the water. The green twisting coils in the background were added to give a sense of opposing movement to the overall piece.

Shapes

For the background coils I used slices of a torus assembled in a simple macro to create an interesting pattern, which I then replicated, rotated, and translated into position.

The schooling sea-things are random blobs with 5 sphere components each. They were assembled into schools by a macro, and the resulting union objects were flattened and stretched until they looked right to me.

Colors

Using the eyedropper tool in a photo editor I sampled selected colors from a photo of some small islands just off the Florida Keys for that realistic tropical feel. I used the RGB color components as pigment values for the objects and environment in the scene.

Lighting

I used a standard main light/fill light setup, and enhanced the highlights and colors with 4 additional spotlights positioned appropriately.