Yes you can.
You can catch it almost anywhere, but you need the good rod to catch it.
you cant catch it in platnium but you can trade it
you cant
no
no ditto is there
you get it from a fossil
Catch a wild magby
there are many places to catch a barboach but where i caught mine was by eterna city sort of where the fishermen are,you have to use a good rod
You can't you would have to catch one in Pokemon Heartgold or Pokemon Soulsilver and trade it to Platnium
No, you'll have to trade it from Platnium. Which in Platnium you find it in the Rock Peak Ruins.
top of mt cornet
you continue on to the next gym