Surf from Olivine
cianwood
Cianwood City
you have to surf to cianwood
The Pharmacy is in Cianwood City.
In Pokémon SoulSilver, you will get the Fly HM in Cianwood City but only after defeating Chuck, the Cianwood Gym Leader.
You can find mantyke on cost of cianwood city
Surf to Cianwood and visit the pharmacy there.
in the caves
You get it from defeating Chuck in Cianwood City from a lady.
surf from olivine to cianwood
You need to go to Cianwood Pharmacy and get the Secretpotion.
I'm not sure but I think cianwood city