A fish themed mural in Floridale Elementary School proides privacy between the teachers lounge and common hallway. Turning the teachers lounge into an aquarium, the painting on the glass was done on the inside of the lounge to protect it from little fingers. Painting on cinder block walls does pose a bit of a challenge when it comes to executing perfectly smooth linear edge. But it's not impossible.
Kids love species they can recognize from cartoons. While I don't paint commercial characters, every clown fish is a "Nemo"!