i cant remember, but you can find nidoran and it's evolutions after you beat the game in the area around the resort area and survival area. they're in the grass and stuff (you might have to use the poke radar)
Both the female and male Nidoran can be found via Pokeradar on Route 201.
Use Pokerader on route 201
You can catch a nidaran by using a pokeraddar on route 201.
There is no trainer in platinum that is willing to trade a munchlax.
you can find the trainer with the misdreavus in platinum in hearthome city i believe
Sorry but there isn't a trainer with a bagon in platinum.
go to rt 201 and use your pokeradar in the grass there. when the patch sort of sparkles that is your best chance to get a nidoran. reminder they are only lvl 2. summary: rt 201, pokeradar, sparkly patch, nidoran
no one no trainer has a kingdra in Pokemon platinum exept for me :P
The trainer in victory road
A trainer has it in their party on route 221.
A trainer on iron island has hippotas
A Trainer on route 220