Fake Pokemon sprites : Electric dragon !

[Hoeloe]

No Pokemon 'grew' colors between games. All of there official art depicted them with all of the colors we now see today, the gameboy's limitations just forced them to use a certain amount of colors.

I guess I didn't make myself quite clear on the colouring aspect. What I meant was that they picked colours that could more-or-less be interpreted with a single colour palette. Notice how much of Blastoise's shell is black, or at least darker than his skin, and much of his inner body is white?

The problem with your dragon is that yellow and blue lie on opposite sides of the colour spectrum, making it seem an unrealistic design for a generation 1 styled pokemon, as it is impossible to convey such a massive colour difference without using more colours.

The number of colours is also not, on it's own, relevant. They were limited to certain palettes of colours too.

Your bringing up Blastoise strengthens my other point, though. Look at him again. Does that REALLY look like a simple design to you? Segmented arms, knee caps, reasonably complex shell rim. The first gen pokemon weren't simple, they just didn't consist of spikes, robot machinery and lots of bright colours.