This easy Blackened Mahi Mahi recipe is buttery and flaky with a seasoning that creates a spicy, crispy crust. This simple dish is cooked in a cast-iron skillet, resulting in delicious flavor and saving you from the heat of outdoor grilling. Top this sweet-tasting fish with mango salsa, or use it in your favorite taco recipe.

Blackened mahi mahi is served on top of white rice for dinner.

As I unloaded my groceries I looked at the fillet of meaty mahi-mahi and knew there was only one seasoning that would suffice…

A spicy Cajun blackened seasoning.

It has just enough spice and heat without being too overwhelming.

And while grilling it up would taste incredible, this scorching Texas heat makes you want to retreat indoors in the summer.

So instead, a cast iron skillet was used to get a gorgeous crusty char on the outside of the seafood while still keeping the fish ultra flaky.

What is Mahi Mahi?

The mahi-mahi is also known as the common dolphinfish and is found in tropical waters. It is similar in flavor to grouper or snapper. When cooked with blackened seasoning, it is a delicious main dish.

Mahi mahi, blackened seasoning, butter, and salt are the ingredients for this recipe.

Ingredients

To make this Blackened Mahi Mahi recipe you need:

  • Mahi-mahi. You want the thicker portion of fish, not the part that’s over the rib cage. This section tends to have lots of little bones that are very difficult to remove and unpleasant to accidentally bite into.
  • Blackened seasoning. You can either make your own blackened seasoning at home or buy a store-bought variety. No matter what you use, be sure to taste it to see how spicy it is. Add more or less depending on your preference.
  • Butter. Because butter makes everything better, especially when blackening things! Salted or unsalted work. You can also use a dairy-free vegan buttery stick if avoiding dairy, or even sub for a high smoke point oil such as avocado oil.
  • Lemons. These might just seem like a garnish, but they add a lovely note of acidity just before serving to balance out the buttery flavors of the fish.

How to Make

The basic steps for making Blackened Mahi Mahi are simple to follow:

Cut into Filets

You will want to slice the mahi-mahi first. Try to make them all the same size for consistent cooking. It is not necessary to remove the skin. It will also come off easily after cooking.

Use a paper towel to dab the mahi-mahi before adding the seasoning blend. Removing this excess moisture will help the spices stick better and give the fish a crispier sear.

Sprinkle with Seasoning

Cover mahi mahi fillets with blackened seasoning. You can make your own blackened seasoning in a small bowl with ingredients you likely already have in your spice cabinet like paprika, onion powder, garlic powder, thyme, oregano, black pepper, and cayenne pepper.

Or, opt for a store-bought version. Either way, be sure to taste the spice blend before using it so you end up with the desired flavor.

Lay the fish fillets on a cutting board skin side down. Thoroughly rub the seasoning in so it won’t shake off while cooking. If your spice mix doesn’t include salt, be sure to add some to the mahi-mahi, as well.

Sear in Skillet

Add butter to a cast-iron skillet and heat the pan over medium-high heat for at least 1 minute. The skillet needs to be hot to prevent the fish from sticking and also get that gorgeous sear.

Add the mahi-mahi to the skillet, skin side-up. Cook for 4-5 minutes. Flip the fillets over so they are skin-side down. Continue cooking for 3-4 more minutes more or until cooked through. Watch the fish carefully as different thicknesses require varying cooking times.

You will know the mahi-mahi is cooked when the meat flakes easily when pressed with a fork. Alternatively, use an internal thermometer to check for a temperature of 137℉. Remove the fish from heat as soon as it reaches this so it doesn’t dry out.

Serve and Enjoy!

Serve this blackened mahi-mahi up over a bed of instant pot white rice with a topping of Mango Salsa (or even Mango Avocado Salsa!) for a quick 30-minute dinner!

You can even pair it with a Lime Crema and some Fish Taco Slaw for some epic Mahi-mahi Fish Tacos.

Blackened Mahi Mahi is topped with mango salsa.

Meal Prep and Storage

  • To Prep-Ahead: Make the seasoning mix beforehand so it is ready. You can slice the fish into fillets a couple of hours before cooking and keep them covered in the fridge.
  • To Store: Place whatever is leftover in an airtight container and place them in the fridge for up to 2 to 3 days.
  • To Freeze: While this fish is best enjoyed immediately, you can put mahi-mahi in a freezer-safe container and store it in the freezer for up to 3 to 4 months.
  • To Reheat: Warm up thawed mahi-mahi in a skillet on the stove, or place it in a 275℉ oven for about 15 minutes.
Mahi mahi is shown in a cast iron skillet after cooking.

FAQs

Is blackened mahi-mahi good?

Mahi-mahi is a mild and somewhat sweet fish. It is stronger than halibut and is delicious with spices like blackened or Cajun seasonings.

What is meant by blackened fish?

The term blackened refers to the spices on the outside of fish that make it turn a dark brown color after cooking. It is not burned. Blackened seasoning is comprised of paprika, onion and garlic powder, cayenne powder, and herbs like basil, thyme, and oregano. It is delicious on protein, vegetables, or potatoes.

Is blackening fish healthy?

Fish is an important part of any diet because it is full of healthy fats, vitamins, and minerals like potassium. When you blacken seafood, you get lots of flavor while avoiding unhealthy cooking methods like frying.

Expert Tips and Tricks

  • DIY seasoning. It is simple and healthy to make your own mixes like blackened seasoning for this recipe.
  • Keep it even. Be sure to cut the mahi-mahi into similar-sized pieces for consistent cooking.
  • Heat it up. Heat up the skillet well before adding the fish so it doesn’t stick.
  • Grab a slice. Serve this dish with a fresh lemon slice to balance out the butter.
  • Top it off. Pile a heaping spoonful of Mango Salsa on this fish when plating.
Blackened mahi mahi is served fora healthy dinner with homemade mango salsa.

What to Serve with Mahi Mahi

Round out this dish by serving it with any of these sides:

More Fish Recipes

Try any of these healthy and delicious seafood courses next:

Tap stars to rate!

5 from 6 votes

Blackened Mahi Mahi Recipe

This easy Blackened Mahi Mahi recipe is buttery and flaky, and the seasoning creates a spicy, crispy crust. This simple dish is cooked in a cast-iron skillet, resulting in delicious flavor and saving you from the heat of outdoor grilling.
Yield 4 servings
Prep 5 minutes
Cook 10 minutes
Total 15 minutes

Ingredients 

  • 1 lb. mahi mahi
  • 1 Tbsp. blackened seasoning
  • ¼ – ½ tsp. salt to taste
  • 2 Tbsp. butter or oil
  • Lemon wedges optional
  • Fresh parsley optional

Instructions 

  • Cut the mahi mahi into 4 equal-sized filets and pat the fish dry with a paper towel.
  • Sprinkle blackened seasoning and salt, if seasoning does not already include it, over the filets and rub it into the fish.
  • Melt butter in a cast-iron skillet over medium-high heat. Wait for at least 1 minute so butter is heated through. Add the mahi mahi to the skillet, skin side-up, and cook for 4-5 minutes. Flip the filets over and continue cooking for 3-4 more minutes or until cooked through.
  • Serve blackened mahi mahi with lemon wedges and a sprinkle of fresh parsley. Enjoy!

Tap stars to rate!

5 from 6 votes

Video

Notes

Meal Prep and Storage

  • To Prep-Ahead: Make the seasoning mix beforehand so it is ready. You can slice the fish into fillets a couple of hours before cooking and keep them wrapped in the fridge.
  • To Store: Wrap whatever is leftover and keep in the fridge for up to 2 to 3 days.
  • To Freeze: While this fish is best enjoyed immediately, you can tightly wrap mahi-mahi and store it in the freezer for up to 3 to 4 months.
  • To Reheat: Warm up thawed mahi-mahi in a skillet on the stove, or place it in a 275℉ oven for about 15 minutes.

Nutrition

Calories: 149kcal, Carbohydrates: 1g, Protein: 21g, Fat: 7g, Saturated Fat: 4g, Polyunsaturated Fat: 1g, Monounsaturated Fat: 2g, Trans Fat: 1g, Cholesterol: 99mg, Sodium: 1251mg, Potassium: 474mg, Sugar: 1g, Vitamin A: 389IU, Calcium: 19mg, Iron: 1mg

Nutrition information is automatically calculated, so should only be used as an approximation.

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Comments

  1. 5 stars
    Not only was this an easy recipe the dish tasted amazing. Mahi-Mahi-mahi happened to be in sale at my local grocery store this week and my family is really excited to enjoy this meal again. Thanks for sharing this recipe.

    1. Yay! So happy to hear you enjoyed the recipe, Carmen! I love that it’s so easy, and yay for sales! Thanks so much for taking the time to leave a comment and rating!