Dewgong can be caught at the Seafoam Islands and Icefall Cave. Your best bet is to catch one at Icefall Cave, as it has a 20% chance of appearing there.
Seel evolves into Dewgong at level 34.
you can only find Seel i believe... then you can evolve it to a dewgong, I highly doubt you can find a wild dewgong =/
There are a few places you can find a dewgong in on Pokemon Platinum version. You can find him on Victory road, route 226, and route 230. If you catch a Seel you can also get Dewgong by leveling Seel up to level 34.
Dewgong doesn't evolve. - Pokemon Guru
Piplup does not exist in Pokemon LeafGreen or FireRed.
No, you cannot find cyndaquil in LeafGreen.
you should go to gamestop
Dewgong evolves from seel
LeafGreen version does not have Growlithe.
In the grass...
You cannot catch houndour in Pokemon leafgreen either get one from Pokemon emerald or Pokemon colosseum.
If you go to the Seafoam Island, you can find Seel (Isn't an Ice-Type, but it's evolution Dewgong is), Jynx and of course the most powerful of all, an Articuno in level 50. The only other Ice-Type is Cloyster, but it's pre-evolved form Shellder can only be caught in FireRed. You can also find Seel and also Dewgong I think in the Icefall Cave.