I made this for the 'Human - Featherless Biped' challenge.

150×150px, 18 colours (17 + transparency)

I've started with the idea of a koi with red and black pattern. On drawing the raw body contour i switched to a golden white one. So there were more available colors and less noise for the shadow or feather patterns.

To add more dynamic I've oriented on features of a butterfly koi, also had a look on fighting fish.

Normally I wouldn't pixel out the structure of the scales, because it produces to much noise. In pixel art in this size it is hard to distinguish between scales and feathers. On birds fearthers are mostly seen on the end of wings and tail, sometimes structure. Most areas on a bird look uniform. With this in mind I decided to subtly indicate the feathers on the body. Prominent feathers I've added on the wings, as lose feathers and on the tail ends. I also added an alula as bird wing feature to a fin.

Transparency works on dark backgrounds. Tested with black, the dark blue and dark green of given palette.

Yes Pete the worm has eyes. If the fish has feathers, why not?