I've always wanted to learn 3D animation, so I decided to turn a doodle of mine into an SVG animation. The fish are originally 3D objects in Blender, I then used Freestyle SVG Exporter to create animated SVG's. It required some tweaking of the SVG code and filling in colors in Inkscape but finally I got something I was happy with.

The original doodle:

I then created a semi-3D fish for ease of animation:

And after animating the 3D fish I used Freestyle to export the outline as an SVG. I then had to open each layer in Inkscape and filled in the dark spots.

This is the result: