Pokemon Diamond & Pearl: By Surfing - Golduck Using Old Rod - Magikarp Using Good Rod - Magikarp and Goldeen Using Super Rod - Gyarados and Seaking Pokemon Platinum: By Surfing - Golduck and Psyduck Using Old, Good, or Super Rod - Magikarp
There isn't a Lake of Rage in Pokemon Platinum. But in the Resort Area, there is a place similar. It is that big Lake in the middle. Down part is, only Magikarp lv. 1-100 can be found there.
The Resort Area
Your villa is in the resort area
It's a level 100 Magikarp.
i think he is near resort area
It is a level 100 magikarp.
The area of Saddlebag Lake Resort is 36.3 square kilometers.
There isn't a Lake of Rage in Pokemon Platinum. But in the Resort Area, there is a place similar. It is that big Lake in the middle. Down part is, only Magikarp lv. 1-100 can be found there.
The area of Greenbo Lake State Resort Park is 13.476 square kilometers.
The area of Buckhorn Lake State Resort Park is 3,464,109.0975744002 square meters.
You need to find the Reapers Cloth around Lake Aucity or the Resort Area and trade it.
The area of Barren River Lake State Resort Park is 8,850,474.9957888 square meters.
Pokemon #79 in Diamond is Seaking. You can find it on routes 203, 204, 209, 212-North & 214, Twinleaf Town, Resort Area, Lake Verity, Lake Acuity, Lake Valor, and the Spring Path (Fish with super rod).
In the Desert Resort somewhere
No.
you have to find all the Pokemon then talk to the guys blocking the resort area
in the servile area