Watercolor Tutorial: How to Paint a Fish Step by Step

Learn watercolor techniques to paint a stunning fish using only two colors, with tips for mixing paints on paper to create a flowing underwater effect

The natural movement and flow of watercolor lends itself perfectly to underwater paintings, mirroring the movement of the ocean and its organic shapes. This is why UK-based graphic designer and watercolor artist Inga Buividavice (@inga_buive) chooses watercolor to capture the beauty and versatility of the natural world.

In this tutorial, Inga teaches you how to easily paint a watercolor fish from scratch. Guiding you from your initial sketch to the finishing touches, she shows you how to mix colors on the page to create an underwater effect, tips for adding details including scales, and ideas for finishing touches to enhance your composition. Watch the video below:

1. Sketch a rough outline sketch of your fish

Sketching the fish out first on the paper will give you a guide for where you want to paint. Do this lightly though so that the watercolor stands out over the pencil.

When sketching, don’t add too much detail, and try to leave the tail out—you want this to be a free-flowing shape created from the watercolor later on.

2. Apply the color

To begin, Inga starts with painting the body and then branches out to the tail. She leaves the fish’s eye until toward the end, noting that the shape she wants isn’t perfectly round to allow for a more natural finish.

You can create beautiful effects while keeping the colors simple. Inga uses just two colors (blue and pink) for her watercolor fish, but applies more or less water to create varying shades and depths throughout.

She mixes the colors directly on the paper using the wet-on-wet technique to make the most of the medium, allowing colors to bleed and blend into each other. Keeping the paper wet allows for the colors to flow and create a beautiful water-like look to the fish. On the other hand, drier paint doesn't spread as much and allows for more control.

Top tip: keep a tissue close by to help lift off mistakes and blot away any excess paint.

3. Add details using different brushstrokes, graphite pencil, and posca pen

Once you’re happy with your base colors, allow the painting to dry so that you can add detail over the top.

Inga creates fish scales over the top of her painting using a small oval brush in a dabbing motion. She also adds lines that flow from the body of the fish out to accentuate the tail and add structure to the shape of the fish.

Using a graphite pencil, Inga emphasizes small details on the fish such as some lines on the tail and scales. She also highlights extra details with the help of a pale-colored posca pen.

4. Add finishing touches to enhance the composition

Once you’re happy with the fish, check the composition of the painting overall—what can you add in the blank spaces to balance it out? Inga uses free-hand techniques to paint some seaweed and bubbles at the bottom and top of the page.

Finally, she finishes the piece with some watercolor splash marks, which work well with this underwater-themed painting. A tip she gives here is that, if the splashes don't fall as you'd like, you can always give them a helping hand by tweaking the shape of each splash with a small brush.

If you enjoyed this tutorial, check out Inga's course Artistic Floral Watercolor: Connect with Nature. Throughout the course, she teaches you watercolor painting techniques to create organic botanical compositions that capture the beauty of the natural world.

Disocver more watercolor resources

- Learn basic techniques, tips for fixing mistakes, and more with 20 free watercolor painting tutorials for beginners.

- Combine contemporary watercolor techniques with observational drawing to create realistic botanical portraits in Julia Trickey's botanical watercolor course.

- Explore naturalist illustration techniques and learn how to paint whales in watercolor in Antonia Reyes' online course.