- Season catfish fillets with ½ teaspoon of salt and ¼ teaspoon of cayenne pepper.
- Set aside on a wax paper-lined baking sheet.
- Heat oil in a dutch oven or a large, heavy saucepan over medium heat.
- Add onion and sauté for 5 minutes or until softened.
- Add garlic, bell peppers, fennel or celery and season with salt and cayenne pepper to taste.
- Cook, stirring often, for 5 minutes.
- Stir in orzo and flour and cook for 2 minutes or until orzo is coated with oil and just starting to color.
- Add wine and tomatoes with their liquid, breaking up tomatoes with a spoon.
- Add chicken stock, water, saffron, if using, and orange zest and bring to a boil.
- Reduce the heat to medium-low, cover and simmer for 10 minutes.
- Add catfish and simmer for 6 to 8 minutes or until fish flakes easily when tested with a fork.
- Stir in marjoram and serve.