Route 132, 133 and 134 (Left of Pacifidlog Town. Right of Slateport) You have to fish for it with a Super Rod
you can get a horsea underwater. but only in sapphire.
you have to go to pacifidlog town and surf then you'll run into a horsea and that's how you get a horsea.
Horsea evolves into Seadra starting at Level 32.
you can catch horsea in ocean current with fishing.
You can capture horsea at the safari zone look for the water on the western portion of the safari zone use the good or super rod to hook up horsea.
Yes, it evolves into Seadra at level 32.
In Firered/Leafgreen & Ruby/Sapphire its level 43
magickarp horsea tetecool starmie shelder the rest i forgot :P
catch a dragon Pokemon such as horsea and Bagon until you get one holding a dragon scale.
you trade seadra holding an dragonscale. Where to find a dragonscale: some wild horsea/gyarados/bagon hold them, but its rare.
In HeartGold or SoulSilver: Catch a wild Seadra, Dratini, Dragonite, Horsea, Dragonair, or Kingra holding the item. Or successfully find and catch a Horsea in the Winner's Path PokeWalker route. In Diamond, Pearl, and Platinum: Catch a wild Dratini, Dragonair, Seadra, or Horsea holding the item. In FireRed and LeafGreen: Find one on the Water Path. In Ruby, Sapphire, and Emerald: Catch a wild Horsea or Bagon holding the item.
First of all it depends on what route your fishing in but you catch these pokemon: Magikarp, Staryu, Carvanha, Horsea, Psyduck, Goldeen.