For the stock: In a medium-size saucepan over medium heat, heat butter until melted. Next, remove shells from shellfish and add to pot. Chop onion into quarters and add to pot along with carrots, celery, fish stock, water, and salt and pepper. Bring stock to boil. Once boiling reduce heat to simmer and allow to simmer for 1 hour. After stock has simmered, strain the stock into a bowl and set off to the side to be added to the soup later on.
In a large saucepan over medium heat, heat butter and olive oil. Once the butter and oil is hot add the minced onion and garlic. Allow the onion and garlic to soften, stirring occasionally for roughly 3 minutes.
Next, add the tomato paste, paprika, curry powder, and wine to the pan and allow to simmer for roughly 5 minutes. Next, add the reserved stock and simmer for 30 minutes.
Once soup has simmered, add shrimp and cook for another 5-10 minutes. Remove soup from heat and allow the soup to cool slightly before stirring yogurt into the soup (this will help ensure that the yogurt does not separate). Serve immediately and top with a drizzle of cream and chopped chives. Add additional sea salt and pepper to taste.
Note: To maintain the smooth, creamy texture of the Green Mountain Creamery Skyr Yogurt in this soup make sure to add the yogurt at the very end after the soup has been removed from the heat, and has cooled for a few minutes. It is also helpful to remove the yogurt from the refrigerator and allow it to reach room temperature before adding to the soup. This will help prevent separation and will result in a smooth and creamy soup.