First, you need to beat the Elite 4 and have the super rod.
Then continue to Mt. Coronet, and go to the waterfall.
Surf next to it, but DON'T USE WATERFALL.
Use the super rod in the waterfall to catch a Lv 20-21 Dratini.
Dratini evolves into Dragonair at level 30.
dragonair
Dragonair are found rarely at Mt. Coronet.
No.
Dragonair does not learn Dragon Rush in Pokemon Leafgreen. However, it can learn the move in Pokemon Diamond, Pearl and Platinum at level 39.
You catch it in mt cornetbut its quite rare
Dragonair evolves according to the level it reaches and once it reaches Level 55 it will start to evolve into Dragonite.
somewhere in Mount Coronet is on the 4 floor a waterfall. use the super rod and there is you're Dragonair. (5% chance)
at lvl 55dragonair evolves when he/she or he_she is level 55
Mt. Coronet you might need to use one of the fishing rods
In Pokemon diamond you can get a drattini by fishing with super rod in a lake with a waterfall in a cave on mt. stark
Mt. Coronet 4F (By Waterfall)http://pokemon.marriland.com/diamond_pearl/pokedex/148/
Dratini evolves into dragonair and dragonair evolves into dragonite