Salamence can only learn Hydro Pump as an egg move in Pokemon Emerald.
The only Pokemon that can learn Hydro Cannon are: Blastoise, Feraligatr, Marshtomp, and Empolion.
defog is not in emerald,
Swampert does not learn Hydro Pump.
You will have to trade or make it learn hydro pump
Salamence can only learn Hydro Pump as an egg move in Pokemon Emerald.
You have to breed it with a Pokemon that knows hydro pump like a male gyarados or lanturn with a female sharpedo. When the egg hatches I think you will have a carvahna with hydro pump.
Lv.40
Yes there is Arceus and Mew. In Pokemon Sapphire Ruby and Emerald Sharpedo and Tropius can learn all 8
the best moves he can learn is hyper beam,fissure,earthquake,facade or hydro cannon (i think)
Sharpedo at lvl 48
The only Pokemon that can learn Hydro Cannon are: Blastoise, Feraligatr, Marshtomp, and Empolion.
defog is not in emerald,
Most water types can like sharpedo.
Swampert does not learn Hydro Pump.
You will have to trade or make it learn hydro pump
Sharpedo doesn't learn waterfall by level-up.