No you can't but you are able to trade it from Pokemon fire red or leaf green
Pallette Town with the Super Rod. (Yes, you need the Super Rod in Fire Red.)
Super Rod.
You fish for it in the town the third gymleader is with a super rod.
You could catch a Shellder at Valley Windworks only by using your super rod
Fish with the super rod of the Vermillion docks.
use a super rod in that pond of water
Shellder appears in the bodies of water in the lower part of Route 205, the Valley Windworks, and Fuego Ironworks. You need a Super Rod to catch one.
route 205 south, valley windworks, fuego ironworks (fish with super rod) it's rare good luck :)
use a super rod behind the valley windworks use surf to get there
Pallet Town with Super Rod in FireRed only. Also on Route 47 in HG/SS. Can be caught with the Super Rod, but can be caught with only 6 badges with the good rod. Rare though.
I think super rod. Anyway, that's what you need in red version, but it probably won't make any difference to blue version.
You use a good rod in vermillion city, and you have a good chance of finding it. This is the easiest way to get shellder in yellow. And just in case you were wondering, you evolve shellder into cloyster with a water stone.