you can't. sharpedo was released in ruby & sapphire witch came after gold & silver.
you can get sharpedo at mossdeep island in sapphire,ruby and emerald.At lake valor in diamond,pearl and platinum.And last you can't find sharpedo in firered and leafgreen
TRADE IT FROM RUBY OR SAPHIRE.
you have to have a level 50 blaziken and sharpedo
wailmer and sharpedo
I know in emerald you can at Mossdeep with a super rod.
lvl 35 sharpedo
Carvanha evolves into Sharpedo at level 30.
Use the super rod on the route west of fortree city.
Ruby, sapphire and emerald you can find a Pokemon called carvanha and sharpedo both of which are sharks.
In Pokemon Ruby, Sapphire and Emerald Sharpedo can be found in a lot of Routes with the Super Rod. Most of these Routes that you can find Sharpedo in with a Super Rod are Routes 122 to133.
You can easily find them with the use of a Super Rod off the coast of Mossdeep City. They have a 30% find rate.