The reason we are telling the OP to put the first snake with a blue eyed leucy producing snake is because it looks a lot like a "Special" or a "Russo".
Putting it with a fire would not unlock or prove anything. It would only give the OP more fires and possibly more of whatever that snake is if it's genetic.
So in this case, it makes more sense to first pair that snake to something in the blue eyed complex to find out if it is what the OP is thinking it might be.