I'm currently working on a Lunar Lander Clone that'll be underwater themed. This image directly below is the first background fish I made for the game, and the first fish I've made using pixel art.
The image below this text is the reference image I used for my Fish. I took the general shape of the Fish's face but diverted from the reference when creating the back half of the body.
I'm pretty happy with how this animation turned out. I used a star sprite from Kirby's Tilt n' Tumble as a reference but the final result looks quite different.