Darkened Water

1. Black background

Fill the background with black

2. Clouds

Filter/Render/Clouds

3. Difference Clouds

Filter/Render/Difference Clouds

4. Repeat step 3

Press Ctrl+F to repeat step 3

5. Duplicate Layer

Duplicate layer

6. Plastic Wrap

Change top layer to screen and Filter/Artistic/Plastic Wrap...20/15/15

7. Chrome

Change back to bottom layer and Filter/Sketch/Chrome...10/10

8. Color Burn

Change top layer to Color Burn

9. Hue/Saturation

Switch back to bottom layer and Ctrl+U and then select colorize...205/50/50

You should be left with something like