Fascinating. How do you achieve that effect? Food coloring? Colored lights?
Please reveal the secrets. I would love to learn how to do this.

Glad to tell.... I use a piece of glass that I have spray painted black on the underside. This gives me a black "background" with a smooth glossy top. I point the camera at a specific point... I use something for focus and leave it on manual focus. I put a small amount of milk (sometimes thickened with something) and add drops of food coloring. Then I release a drop of milk into the food colored milk and hope for the best.