What trainer has a barboach in Pokemon diamond

there s a trainer with barboach, but yo need to beat the fifth gym leader and have surf.go to mount cornet by Orbergh or Eterna city. I realy don`t know where it is. go through that and if you see water try to get to it and then surf on it and if you see a trainer that is a fisher man, battle him and he mite have a full hose

more detailed: go to orbergh city you must have a bike and surf, go through mt. cornet when you get out go down until you can surf on the lake then surf to the small ledge that has one fisherman on it he will have barboach