I actually did play around a bit with the tissue paper fish from the promo, removing the background to see what it would look like.
Some other promo and merchandise material also used the same style of fish in a cartoon version, like this lanyard.
It could probably be recreated without too much difficulty, but I don't think it would look quite right with vector graphics. Using a drawing pad would probably look more natural in order to capture the nuances in the shape.