Blackened Fish Tacos with Avocado Lime Sauce

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A super simple blackened fish taco recipe served with a creamy avocado lime sauce to drizzle on top. Firm white fish is coated with a spicy seasoning blend and pan-fried until lightly charred on the surface for maximum flavor.

Two blackened fish tacos on plate

This fish taco recipe is inspired by a food adventure just south of the border in Baja California, Mexico. My husband and I stopped at several small seaside villages like Puerto Nuevo for langosta (lobster) and pescado (fish). The food in Baja is incredible. Street cart vendors selling elotes and tacos al pastor, carnitas, carne asada, lengua, and most restaurants have whatever your heart desires.

This recipe uses a Mexican-inspired spice blend that works with any type of fresh fish. This time I choose to Mahi Mahi for its lean flakey texture, which is a match made in heaven rolled up in a corn tortilla and all the taco fixings. Taco Tuesday is never going to the be the same from here on out!

person adding spices to fish fillets laid out on a sheet pan

Ingredients for the blackening seasoning

The best blackening season combines smoked paprika, brown sugar, garlic, onion, cumin, chili powder, salt, and black pepper. It layers on a flavor explosion that takes a mild white fish to bold and rustic in taste.

If you want more heat, just add more chili pepper, or better yet, some cayenne pepper. If you’re following a Paleo or Whole30 diet, you can omit the brown sugar. The sweetness is there to balance the savory seasonings and helps to brown the surface more quickly.

fish fillets cooking in a cast iron skillet

Mahi Mahi only requires a few minutes to cook before it gets dried out, so keep an eye on it. Start with a nice hot pan by pre-heating over medium-high heat for a few minutes until you can feel the heat rising. I use a cast iron skillet, however, stainless steel or nonstick pan will work too.

Press the fish against the pan

Add enough oil to coat the bottom of the pan, and then heat until almost smoking. Carefully add the fish and gently press on the fillet with a spatula for a few seconds so the flesh can make direct contact with the hot pan.

This also helps release some of the moisture from the surface of the fish so the meat can brown evenly. Flip the fish and finish cooking. This process takes about 5 to 6 minutes max.

Fish tacos on a plate with shredded lettuce and sliced tomatoes on top

Avocado lime sauce

A quick avocado lime sauce can be made using a blender to create a smooth and creaming topping. It’s a simple combination of sour cream, ripe avocado, cilantro leaves, fresh lime juice and zest, and serrano peppers.

Crema or plain Greek yogurt can be substituted for the sour cream. Any type of pepper can be used, just adjust the amount to your heat tolerance, this sauce is mild. The fresh, tart and creamy sauce cool down the spices on the fish for a tasty pairing.

Additional toppings

close up of a fish fillet on top of a tortilla with sauce

More Mexican recipes

Why do you add brown sugar to the seasoning?

The sugar not only adds a sweet molasses flavor but also speeds up browning on the surface of the mahi mahi. The desirable brown pigments appear at around 200°F (93°C) when the fructose in the brown sugar caramelizes to create a beautiful quick crust.

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Blackened Fish Tacos with Avocado Lime Sauce

A super simple and flavorful recipe for blackened mahi mahi fish tacos that you won't need to head to Mexico to enjoy!
Pin Print Review
3.96 from 193 votes
Prep Time20 mins
Cook Time10 mins
Total Time30 mins
Servings 8 tacos
Course Entree
Cuisine Mexican

Ingredients

Avocado Lime Sauce

  • ½ cup sour cream
  • ¼ cup water
  • 1 avocado, medium-sized and ripe
  • ¼ cup cilantro leaves, loosely packed
  • 2 tablespoons lime juice, fresh
  • ½ teaspoon lime zest, about 1 lime
  • ½ teaspoon minced serrano pepper, seeded

Fish Tacos

  • 1 ½ teaspoons smoked paprika
  • 1 ½ teaspoons dark brown sugar
  • ½ teaspoon garlic powder
  • ½ teaspoon onion powder
  • ½ teaspoon kosher salt
  • ¾ teaspoon cumin
  • ¼ teaspoon chili powder
  • ¼ teaspoon black pepper
  • 1 ½ pounds Mahi Mahi filets, cut lengthwise into smaller pieces if needed
  • 1 tablespoon vegetable oil
  • 8 corn tortillas, 6-inch
  • 8 lime wedges
  • 1 cup tomatoes, diced
  • 1 cup red cabbage, sliced thin
  • 1 cup green cabbage, sliced thin
  • cilantro, for garnish

Instructions 

  • Add sour cream, water, avocado, cilantro, lime juice, lime zest, and serrano pepper into a blender.
  • Process until smooth, scraping down the sides as needed. Add more water as needed to achieve desired consistency. Transfer to a small bowl and refrigerate.
  • Combine paprika, brown sugar, garlic powder, onion powder, salt, cumin, chili pepper and black pepper in a small bowl.
  • Sprinkle seasoning evenly over both sides of the fish filets.
  • Heat oil in a large cast-iron skillet or sauté pan over medium-high heat.
  • Add fish to pan then cook 2 to 3 minutes on each side or until the desired degree of doneness. The surface will blacken in color quickly so keep a close eye on the fish. 
  • Warm tortillas according to package directions.
  • Divide fish evenly among tortillas.
  • Serve with lime wedges, tomatoes, cabbage, and cilantro.

Recipe Video

Notes

  • Spice blend makes: 2 tablespoons plus 1 teaspoon.

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Nutrition Facts
Blackened Fish Tacos with Avocado Lime Sauce
Amount Per Serving
Calories 172 Calories from Fat 45
% Daily Value*
Fat 5g8%
Saturated Fat 1g5%
Polyunsaturated Fat 1g
Monounsaturated Fat 1g
Cholesterol 65mg22%
Sodium 146mg6%
Potassium 481mg14%
Carbohydrates 15g5%
Fiber 3g12%
Sugar 4g4%
Protein 18g36%
Vitamin A 1350IU27%
Vitamin C 19mg23%
Calcium 60mg6%
Iron 2mg11%
* Percent Daily Values are based on a 2000 calorie diet.

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Jessica Gavin

I'm a culinary school graduate, cookbook author, and a mom who loves croissants! My passion is creating recipes and sharing the science behind cooking to help you gain confidence in the kitchen.

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73 Comments Leave a comment or review

  1. Roseanne says

    We just made this for our daughter’s (17 yr old) birthday dinner. Everyone helped to prepare every step. We left the pepper out cause we thought it would be too spicy, just right for all three! The blackened mahi mahi turned out so delicious! We all thought this dinner was delicious and just right!! This recipe is a keeper! (My 17 yr old probably can make this next time!)

  2. Edie Lang says

    Love this recipe. The spices used for the blackened fish were really good. I had Tilapia on hand so that’s what I used. My husband really liked the Avocado lime sauce. How long can it be stored in the refrigerator?

    BTW, I got your book for Christmas. Between the emails I receive and your book, I am enjoying all sorts of new recipes. I am retired but volunteer at an animal shelter in Auburn CA. I am Shelter in Place, so it’s nice to have all these new recipes to fill my time. Thank you.

  3. Caitlin K says

    We made this dish for dinner tonight using fresh caught snapper as the fish. The seasoning is perfect and the avocado cream sauce went so well with it! Super easy and delicious! I just got the cookbook and can’t wait to try out the salmon version and many others!

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