How to connect generator / rv fuel pump

Thank u all. I will try rock auto. I would love to bring the tank down to see if I can find that nipple to connected there, but I had back surgery a few years ago and am limited to what I can do, and I though about another tank but I think in the long run would b more trouble.
Is there any way to see or find out where the nipple is in the tank, maybe if I know in the area I can look to see if a can find it