In a large stockpot on medium heat add the oil. Saute onion, carrots and celery for about 2 minutes. Add the ginger and garlic and saute for another 30 seconds.
Add the thyme, pepper cream, fish sauce, potato and chicken stock. Bring to a boil.
Add the fish and cook uncovered for about 5 minutes. Season with salt and pepper as desired.
Serve warm with some garlic bread.