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
3.92 from 282 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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Reader Interactions

83 Comments Leave a comment or review

  1. Jamie F says

    Made these tonight and they were amazing! Hubby kept saying how yummy they were too, thanks I’ll be making them again!

      • Caroline says

        Hi, How did you get the skin off the mahi mahi? Yours looks beautifu. I loved the recipe too. Very tasty and not difficult to cook especially when we are in a hurry.

    • Jessica Gavin says

      Hi Lakshmi-You can leave out the brown sugar, you’ll just have a smokier and more savory flavoring. Since there is no sugar, there will be less caramelization on the surface.

  2. Angela says

    This is the third time making them in 3 weeks (once substituted with chicken). Follow the recipe to a T. The best tacos we’ve not only ever made, but have ever had. Easy, healthy, delicious. Awesome recipe.

    • Jessica Gavin says

      Hi Angela- This comment truly made my day, I’m still smiling! I’m so happy that you enjoy this recipe, great idea switching it up with chicken, I’ll have to try it too 🙂

    • Jessica Gavin says

      Me too Eileen! I made the blackened fish last night just to top on a salad, super versatile!

  3. Jeff Scotti says

    My god Jessica, your blackened fish tacos were the bomb!!! So good and so easy to make. I had to share this with my family members, hope you don’t mind. I just know there going to love it. Please keep up the good work… you need to have your own TV cooking show! Thanks again for all your great recipes.

    • Jessica Gavin says

      Hi Jeff! You just made my day even more awesome!!! There’s nothing better than hearing that someone amazing had success with your recipe, thank you 🙂 I’ll keep sharing recipes and hopefully someday I’ll make it to the big screen! I appreciate your support, happy cooking 🙂

    • Jessica Gavin says

      I’m so glad you enjoyed the recipe Claire! The mango jicama slaw sounds amazing! I love TJ for some quick and yummy meal additions 🙂

  4. Carley says

    Thank you so much for this recipe! My favorite place for blackend mahi mahi tacos just closed and this sounds like it would taste so close or possibly better then the fish tacos I used to get there. Thank you again!! I’m so excited to make these for dinner!!!

    • Jessica Gavin says

      Hi Carley! I’m so sorry that you’re favorite restaurant closed! Hopefully you can enjoy this recipe just as much, let me know how it goes!

  5. Stephanie Sirgo says

    I have a large piece of frozen mahi mahi (skin on) – would you cut into filets, skin, and cook in pieces? Or just cook the large piece and then cut after it is cooked?

  6. Angela says

    Hi Jessica. My husband and I love these fish tacos! He was the one who found your website and made them for me. I was wondering if there is any way to thin out the sauce a little bit. I don’t want to change the taste, so I was hoping you had a good recommendation.

    • Jessica Gavin says

      I’s so thrilled to hear that you and your husband enjoyed the tacos Angela! I would say you could add either a little bit of milk, more lime juice, or a combination of lime and water until you get your desired consistency. You could also add a little less avocado or use a light sour cream if it’s really thick. Let me know how it goes!

  7. Priya says

    Really tasty recipe! My husband said they’re the best fish tacos he’s ever had! …and he’s tried his fair share of them! I made a generous amount of the seasoning with less sugar and more chilli. Served with mango radish salsa. Delicious! The bonus was that this took me 20min to make.

    • Jessica Gavin says

      Wow Priya, that is a huge compliment! I’m glad that adding more spices and less sugar still made them tasty. Fast and yummy is always good!

  8. Tricia says

    Made this last night with frozen mahi mahi from Trader Joe’s. I’ve never tried to cook blackened fish before, and your instructions were spot on. Turned out perfectly and my husband was super-impressed. We both loved it and I can’t wait to try it on chicken too! I’ve tried two of your recipes now and both were absolutely delicious. I think I’ll just stay on your site and try a new recipe each night. So many great recipe ideas to choose from!

    • Jessica Gavin says

      Yay Patricia! I like to use the TJ mahi mahi as well. Thank you so much for making my recipes, you made my day with your lovely comment. Let me know what else you try!

  9. Kristina says

    Can I substitute the Serrano pepper for a jalapeño or haberno pepper? Just use less perhaps? Looking forward ro making these tonight.

    • Jessica Gavin says

      Hi Kristina- Yes! The jalapeno pepper is actually not as hot as serranos, so you can substitute 1:1 and add more to taste. Habaneros are much hotter, so I would use less and then add more if you want it spicier.

  10. Connie says

    I saved this recipe months ago but last night was the first time to try it – what have I been waiting for?!!! It was delicious! I substituted some jalapeno for the serrano pepper (because that was what I had) but otherwise followed the recipe. Your short video is very nicely done too! The fish came out perfectly done and so tasty, and the sauce is perfect! Living in FL we miss the authentic So Cal fish tacos but no worries now, this recipe is even better! Thank you!

  11. Michael says

    Wow, Thank you for this amazing recipe. I made these Blackened Fish Tacos for my wife yesterday, and I have to admit these are some of the best fish tacos I ever tasted (my wife agrees!) Simplicity make this recipe a rarity; easy to prepare, flavourful, and fresh. This recipe is going into my standard rotation.

    Thanks again.

    • Jessica Gavin says

      You’re welcome Michael! So happy to hear that the family enjoyed the recipe and that it will become part of the rotation 🙂

  12. Melissa Dixon says

    This is now going to be a staple recipe in our house! The seasoning for the fish was excellent and the avocado cream sauce was to die for!

  13. Angie says

    My husband loves fish tacos and this recipe will be my first try making them so I’m super excited to surprise him. We love crispy seared skin on fish, does this recipe still work if I leave the skin on the filets?

    • Jessica Gavin says

      Hi Angie! Yes, if you like crispy skin, you can leave it on. You may want to add another minute or so to the skin side and only add the seasoning to the flesh side so the skin does not become too charred.

    • Jessica Gavin says

      Hi Jake- I have a variety of recipes, and enjoy using wholesome ingredients. Many of the recipes can be modified to suit your dietary needs. If you have specific questions, please don’t hesitate to ask!

    • Jessica Gavin says

      I would say 2 days in an airtight container, put some plastic wrap between so the sauce has let exposure to air.

  14. Shannon says

    These were so good! I have been teaching my son to cook and when I said this is for dinner he was excited. They were amazing!

  15. John Harper says

    Great recipe! I did sub Mexican crema for the sour cream. You are right about the Avocado sauce. It will darken unless you keep it airtight. I thought about adding some more lime juice to prevent that, but I thought it would change the flavor.

    I posted this on my IG feed, and I thought I’d leave you a message here!

  16. Kay Wakeham says

    This is a great recipe. I really love it. Easy after work dinner. I am from Texas and the spices are just right. Although for certain friends, I might kick it up a bit with more serrano peppers or jalepenos. instead.

  17. Marie Czarnecki says

    I went over the recipe three times, and I don’t see where or what you did with the avocado sauce.. I am not a stupid cook at 80 young but not specified.

  18. Thomas Fennell Jr says

    I’m 17 and love to cook this are great recipes to start on. I’m going to Johnson and wales University in Miami.

  19. Sue says

    This was delicious! I also used Trader Joe’s frozen defrosted Mahi. I substituted jalapeno for the serrano as I couldn’t find any serrano locally. I used Swerve Brown Sugar (sugar-free) and it worked great. I love the dry rub and plan to use it on salmon and chicken. Who knows what else. My husband is not a Mahi fan but this may have converted him 🙂 Thanks for sharing!

  20. Sue says

    These were delicious! I also used the Trader Joe frozen Mahi (defrosted). I used Swerve Brown sugar (unsweetened sugar) and it worked great. Also substituted jalapeno for the serrano. Love the spice mixture! This recipe may have converted my spouse into a Mahi fan 🙂

  21. Bill Z says

    Used my homemade blackening seasoning and added cumin which worked great. Your Crema is delicious but I swapped out yogurt and kefir for the sour cream. This is the first recipe of yours that I have made, twice now. It is very tasty and healthy and I am looking forward to trying more.

  22. Lisa Murphy says

    Hello!
    First time making these delicious fish tacos but definitely won’t be the last!
    I thought it was going to be a lot harder but it was so quick and easy, it will be a regular on taco Tuesday!
    Thank you so much!
    Lisa

  23. Stephanie K says

    My husband and I made this together the other night and substituted a plant-based dairy-free sour cream in the sauce. I have to say that the caramelization on the fish from the brown sugar and the brightness of the crema sauce are SO complimentary! Hubby requested that we put this meal on our regular rotation. p.s. ask the fish counter to remove the skin from the fish to save time!

  24. Christian ross says

    This was definately a good recipie base. I made some changes that really made it pop mainly to the sauce. Instead of chili powder I used ancho chili powder. On the sauce instead of water I used heavy cream and added garlic salt to it. Then I used a hand blender to make the sauce creamy. Nothing but rave reviews from every one in attendance.

  25. Shiloh Hollin says

    These were stellar! What I appreciate most about them, is no deep fat, no breading and no batter; still you get a great flavor and aroma packed crust. I replace the brown sugar with grated pilancillo because it was already out on the counter and used a brilliant red cashmere chili powder from The oaktown spice shop. For the avocado sauce I replaced the serranos with red, ripe Fresno chiles because that’s what I had on hand.

  26. 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!)

  27. 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.

  28. 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!

  29. Michelle M Heiter says

    Jess, you hit this out of the park! So good! My goal was to perfect a fish recipe and this is it! So delicious. I am really enjoying cooking from your website and cookbook. Everything is flavored perfectly.

  30. Dor Berger says

    I needed an easy weeknight meal and a break from the routine. This recipe is a WINNER. Easy and it was delicious. I ran out of pepper but had lemon pepper on hand and it gave it a bit of citrus. Would do that again.
    Thank you so much for sharing the recipe. My entire family loved it.

  31. Angshuman Das says

    Hi Jessica:

    Thanks for your wonderful recipes and the explanations of the science behind them. I have a health-related question in light of the blackened fish. Is charred fish bad for health? I read somewhere that it is linked to cancer risk? Is that right?

    • Jessica Gavin says

      You’re welcome Angshuman! I would consult a physician to ask about the cancer risk of eating charred fish to be sure. For this recipe, it’s more of caramelization of the brown sugar and some darkening of the spices, but it shouldn’t be completely charred or burnt, as the fish only cooks a few minutes per side.

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