no
You get Piplup from the beginning of the game in a Pokeball in a suitcase on grass. It can't be found in the wild without hacking.
the three starter Pokemon are the same in platinum as diamond and pearl. They are chimchar-fire, piplup-water, and turtwig-grass.
You can only get one of these starters in Pokemon platinum: piplup, chimchar, or turtwig. In my opinion it is best to get piplup for type advantage. Example: if you get chimchar your friend (on the game) will get piplup, and chimchar is fire so piplup will win because it is water. Same thing with turtwig, he will get chimchar and grass is weak against fire. But with piplup, piplups only weakness is electricity and niether chimchar, or turtwig is electricity so piplup is your best bet.There is a cheat to get all three of them but I don't know it so the only way you can get piplup if you already have chimchar is to trade with someone who has piplup.
you can start of with chimchar piplup or turtwig piplup would be the worst because its third evolvation is water and steel chimcar would the 2nd best because fire can beat steel and the the best is turtwig cause its evolvation is ground and ground can beat steel and fire
You cannot catch Piplup in any game.
Piplup
in the begining of the game If you want a piplup and a turtwig or chimchar I suggest trading.
when you start the game you can choose a piplup or chimchar or tutwig.
You can get a Piplup on Heartgold by trading it from your Diamond/Pearl/Platinum games.
Put a membner of the piplup family in the daycare together with a ditto.
Piplup is a starter Pokémon so it cannot be caught.
pick it as your starter