Oil slick on water - how to simulate in diorama?

[pascalemod]

As title says, if you want to display on water base an oil leaking out of a ship, oil film or what have you, do we have anything like that as a ready product we can use?

Imagine a wreck, leaking oil out, as the slick is carried with the current. Think 1/700 scale, so small.

I only seen this, but this is a little different scale. Would it be applicable as a method?
https://www.youtube.com/watch?v=tWr53okLdxs

Oil has that rainbow look to it. How does one recreate it, plus the shinyness, on a base thats a watercolor style? Or one has to go with the resin pour and just mix in some black stuff sort of as one imagines it goes with the current?...

My guess would be to 1) paint the water on the waterolor 2) add the sharper dividing black stuff that flows with the current out 3) paint the rainbow effects a little bit with a layer on top of gloss 4) another gloss layer.. .

Or?