There are numerous ways to color a mermaid fin. You could draw each individual scale, import a texture from an image, or just do basic shading. This is just one of many, but it’s my favorite because it’s fast, easy, and a great way to add texture to the tail.

 

First, we start with a base color.

Next, we pick a lighter and a darker color for the shine and shadow, respectively. Make sure they’re not too close to the base color. I used colors from Clip Studio’s additional color set. You can use the color sliders or the approximate color selector if you prefer.

Use the opaque watercolor brush. I’ve found this gives good variation in color density and size. It also blends very well. I’ll list my specific settings at the end.

Using this brush, color circles on your mermaid tail. Vary the pressure to get some circles darker than others. Do this on a layer clipped to the layer containing your base color.

 

Do this with both your lighter and your darker color. This shades the tail and adds texture at the same time.

On the base layer you can add similar dots around the waist to make the scales appear to fade out

Add glow above the scales to make the fin shine!

For the fin use the same colors to shade and shine, but have the base at about 75% opacity. You can add glow to this, too.

That’s it!

 

 

 

Opaque Watercolor Settings

Amount of Paint: 60

Density of Paint: 30

Color Stretch: 40

Hardness: max

Brush Density: 50

Stabilization: 2