Baked Fish with Onions, Peppers, Olives, and Feta

I’ve been making this amazing Baked Fish with Onions, Peppers, Olives, and Feta for years and I absolutely love these flavors. And I think baked fish is always a perfect main dish for a low-carb meal!

PIN the Baked Fish with Onions, Peppers, Olives, and Feta!

This Baked Fish with Onions, Peppers, Olives, and Feta is a recipe I came up with in the very earliest days of my blog, and it’s a favorite quick dinner that I’ve been making it for years. You can make this with any type of mild white fish, and using a topping with finely chopped red onion, red bell pepper, green olives, and Feta adds a lot of flavor to the mild-flavored fish.

There’s a small amount of mayo spread over the fish to keep the topping on, and that also keeps the fish moist when it’s baked at a high temperature. It’s important to start with room-temperature fish pieces, so the fish cooks quickly without the topping ingredients getting too done.

If green olives are a non-starter at your house, please try this baked fish recipe with capers instead. But I hope you’ll try this way of cooking fish, and if you like these flavors and I bet it will become a repeater at your house too!

What ingredients do you need?

(This is only a list of ingredients; please scroll down for complete printable recipe. Or if you use the JUMP TO RECIPE link at the top of the page, it will take you directly to the complete recipe.)

• white fish fillets
• Olive Oil (affiliate link)
• red bell pepper
• red onion (or sweet white onion)
• green olives or chopped Capers (affiliate link)
• Feta
• mayo

What fish can I use to make this baked fish recipe?

I used to use Tilapia for this fish recipe, but now I’d use another mild white fish such as halibut, orange roughy, cod, or sole. Other fish you might use include pollock, barramundi, and mahi mahi.

How low in carbs is this Baked Fish recipe?

This absolutely delicious and easy fish recipe only has about 5 net carbs per serving!

How to make Baked Fish with Onions, Peppers, Olives, and Feta:

(This is only a summary of the steps for the recipe; please scroll down for complete printable recipe. Or if you use the JUMP TO RECIPE link at the top of the page, it will take you directly to the complete recipe.)

1. Take the fish out of the fridge and let it come to room temperature while you chop up the red onion, red bell pepper, and green olives, and crumble the feta.  (Amazing chopping skills in this photo by my nephew Jake!)
2. Heat the oil over medium-high heat and saute the red onion and red bell pepper about 3 minutes.
3. Turn the heat to medium, add the green olives, and cook about 2 minutes more. 
4. Turn off the heat and let the mixture cool a little before you stir in the feta.
5. If the surface of the fish seems wet, blot dry with paper towels so the mayo will stick.
6. Season the fish with salt and pepper and spread a very thin layer of mayo over the top of each piece of fish.
7. Stir the crumbled feta into the onion-pepper-olive mixture.
8. Use a spoon to spread the mixture over the top of the fish, pressing it down slightly as needed to get the topping to stick.
9. Roast 10-15 minutes in a preheated 425F/220C oven.  (Cooking time will depend on the thickness of the fish, but it’s usually closer to 15 minutes unless the fish pieces are really thin.)
10. It’s done when the fish is opaque and firm to the touch and the topping is slightly browned.

Make it a Low-Carb Meal:

For a low-carb dinner, the baked fish would be delicious served with Grilled Asparagus with Parmesan, Lemony Green Beans, or just a simple salad with romaine, radishes, and vinaigrette dressing like you see in the photo.

More Tasty Baked Fish You Might Enjoy:

• Spicy Air Fryer Fish With Remoulade Sauce
• Baked Halibut with Sour Cream, Parmesan, and Dill Topping 
• Baked Salmon with Pesto and Tomatoes

Continue to Content

Print

Yield: 2 servings

Baked Fish with Onions, Peppers, Olives, and Feta

Prep Time 20 minutes

Cook Time 15 minutes

Total Time 35 minutes

I‘ve been making Baked Fish with Onions, Peppers, Olives, and Feta for years and this is easy and tasty for a low-carb dinner.

Ingredients

• 2 large uniformly-thick white fish fillets (see notes)
• 2 tsp. olive oil
• 1/2 cup finely diced red pepper
• 1/4 cup finely diced red onion (or sweet white onion)
• 1/4 cup finely diced green olives (or try chopped capers if you’re not a fan of green olives)
• 1/3 cup crumbled Feta (see notes)
• 2 T mayo (see notes)

Instructions

1. Preheat oven to 425F/220C.
2. Spray small glass or ceramic casserole dish with nonstick spray.
3. Heat olive oil over medium-high heat in a nonstick frying pan and saute red pepper and onion about 3 minutes.
4. Add olives and saute about 2 minutes more. Turn off heat.
5. Put fish in casserole dish and season with salt and pepper.
6. Spread a small amount of mayo evenly over the surface of each piece of fish.
7. Stir feta into red pepper/onion/olive mixture and spread that over the top of fish. (Pile it on so all the mixture is used. It doesn’t matter if some falls off while it’s cooking, but press it down so it sticks as much as it can.)
8. Bake until fish is opaque and white throughout and topping is barely starting to brown, 10-15 minutes. Thinner pieces of fish may be done in 10 minutes, but thicker ones will take the entire 15 minutes.
9. Serve hot.

Notes

I used to use Tilapia for this recipe, but now I'd use another fish such as halibut, orange roughy, cod, or sole.

If your fish fillets are small this is probably enough topping for 3-4 pieces of fish. You can use less Feta if you're not wild about Feta Cheese.

Recipe created by Kalyn.

Nutrition Information

Yield

2

Serving Size

1
Amount Per Serving Calories 349Total Fat 25gSaturated Fat 7gUnsaturated Fat 17gCholesterol 103mgSodium 847mgCarbohydrates 7gFiber 2gSugar 4gProtein 23g

Nutrition information is automatically calculated by the Recipe Plug-In I am using. I am not a nutritionist and cannot guarantee 100% accuracy, since many variables affect those calculations.

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Low-Carb Diet / Low-Glycemic Diet / South Beach Diet Suggestions:
Baked Fish with Onions, Peppers, Olives, and Feta is a tasty low-carb or Keto recipe that’s also a perfect Phase One dinner for the original South Beach Diet. 

Find More Recipes Like This One:
Use Oven Dinners to find more recipes like this one. Use the Diet Type Index to find recipes suitable for a specific eating plan. You might also like to follow Kalyn’s Kitchen on Pinterest, on Facebook, on Instagram, on TikTok, or on YouTube to see all the good recipes I’m sharing there.

Historical Notes for this Recipe:
This recipe for amazing baked fish was first posted in 2007! I’ve made it regularly since then and the recipe was last updated with more information in 2024.

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