In a large saucepan cover potatoes with enough water so they are fully covered. Bring to boil then reduce to a simmer. In a frying pan cook onion and bacon over medium heat until onions are soft. Add to potato mixture.
Once potatoes become soft and the broth has a milky look to it, add cut up fish fillets. Heat until fish fillets are cooked through.
Add enough milk to bring soup to your desired taste and texture. Season with white pepper and serve.
You can use any white fish that you have available.