Heat the vegetable oil in a large pot over medium heat.
Add the chopped onion and cook until soft and translucent, about 5 minutes.
Stir in the minced garlic and cook for another minute.
Add the chopped red bell pepper and diced tomatoes. Cook for 5-7 minutes until the tomatoes break down.
Stir in the sweet paprika and hot paprika (if using). Cook for 1-2 minutes to release the flavors.
Add the fish chunks to the pot, stirring to combine.
Pour in the fish stock or water and add the bay leaves and dried thyme.
Bring the mixture to a boil, then reduce the heat and let it simmer for 20-30 minutes, or until the fish is cooked through and tender.
Season the soup with salt and black pepper to taste.
Stir in the vinegar or lemon juice to brighten the flavors.
Remove the bay leaves.
Garnish with chopped fresh parsley.
Enjoy your meal!