Originally Posted by Fat Alice in Strings
One of the big problems with the tadpole is the level it comes at. In RB, it comes at a bogus Level 15, while in Yellow, it can range from 5-15. In terms of efficiency, this isn't where it's at. Not to mention you have to trade one for a Jynx anyway. It's Gyarados all over again, without the good points that Gyarados has (trashing endgame and monster stats).
RainbowBadge nets you the ability to fish on the water segments of Route 23 for up to L40 Poliwhirl in Yellow. Considering Blaine gets utterly steamrolled by any generic water type, Yellow Poliwag's pretty legit to me imo. RB poli... uh... go to hell.