This is a replacement part for the boardgame "Tempo, kleine Fische" from Ravensburger. This was needed from the kindergarten of my little daughter. Now they have plenty of these little fishes. I've printed the fishes with white colored PLA, so they can paint them in the needed color.
If just searched for a free pic of a fish, converted it to .svg and imported that to TinkerCAD. After that I've figured out the right dimensions.