This is the color theme I want to achieve. (+ the burning red standing out but cannot find the initial betta pic I saw with red too)If you check out photos of dark colored fish, you will notice that they still have specular highlights that are almost white. And so for practice, you should have a full range of tone, from almost black behind and under the fins (occluded areas) to almost white, in bits on the upper surface, even on the tail things.
Well yeah that diffuse specular is what I'm after. Like light fading onto the surface because the surface is so dark that it will absorb most of the light.Well that's not really a good reference photo... there's hardly any light on the fish. I honestly can't see any color. This may be too glossy, but I did this in just a couple minutes. You still get the dark color feeling, but there's light and shadow on it too. Even matte surfaces can have some kind of specular, it's just wider and more diffuse.