Heat a Dutch oven or large pot to medium and add the olive oil.
Add the garlic clove, red pepper, green pepper and onion and sauté for about 5 minutes.
Add the dried pepper paste (or tomato paste and smoked paprika) and cook for 2 more minutes, stirring constantly so it doesn’t burn.
Add the potatoes and fish stock. Bring to a light boil and simmer for 20 minutes.
While the soup is simmering, cut the tuna into 1/2" cubes.
After 20 minutes of simmering, add the fish and cook for 5 minutes or until cooked through. Salt and pepper, to taste.
Serve and garnish each bowl with fresh parsley.