Blackened Mahi Mahi

Name: Blackened Mahi Mahi
Prep time: 5 min
Cook time: 6 min
Total time: 11 min
Ingredients: 1 teaspoon kosher salt; 2 teaspoons smoked paprika; 2 teaspoons garlic powder; 1 teaspoon dried thyme leaves; 1/2 teaspoon onion powder; 1/2 teaspoon cayenne pepper (more or less to taste); 4 mahi mahi fillets (approximately 6 ounces each); 1 recipe cajun seasoning (approximately 2 tablespoons); 2 tablespoons butter; 1 tablespoon olive oil; 1 lemon (cut into 4 wedges)

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Blackened Mahi Mahi, made with homemade cajun seasoning and quickly pan-seared, is a simple, flavorful dinner recipe that comes together in less than 15 minutes.

Just like my recipes for Baked Cod and Baked Salmon, this recipe for Blackened Mahi Mahi comes together to create perfectly seasoned, perfectly cooked fish, for a wholesome, yet FAST dinner.

Blackened mahi mahi on white plate with cheesy grits.

This recipe for Blackened Fish is one of the easiest and tastiest ways to prepare your fish fillets.

Blackened fish simply means to heavily season a fish fillet with a slightly spicy rub and then sear the seasoned fillets in a very hot skillet. As the fish cooks, the spices toast and deepen in color, hence the term blackened.

This recipe for Blackened Mahi Mahi is made with homemade cajun seasoning and then pan-fried quickly. It is full of flavor, buttery, and flaky. Absolutely delicious and so easy to make.

While this recipe for blackened fish is made using Mahi Mahi, you can use the same technique and seasonings with your favorite fish fillet, for a simple, flavorful seafood dinner.

That said, Mahi Mahi is a great choice for blackened fish, as it is a firm-textured, mild white fish that is a great source of lean protein. It takes on flavors well and is not at all fishy. In fact, if you think you don't like seafood, Mahi Mahi is a great fish to ease you into enjoying seafood. 😉

Notes on Ingredients

Ingredients for Blackened Mahi Mahi on white counter.

Mahi Mahi: You want to select fish fillets that are about ½" thick and between 4 to 6 ounces each. You can use frozen, defrosted, or fresh mahi-mahi. While I love using mahi-mahi for this blackened fish recipe, as it is so mild and buttery in texture, you can use any firm white fish such as halibut, grouper, snapper, or seabass in place of the mahi-mahi.
Cajun Seasoning: For the seasoning, I use a blend very similar to my homemade cajun seasoning. It is a bit spicy, so feel free to omit the cayenne pepper to control the level of heat.
Butter: While most blackened fish recipes call for brushing the meat with butter before seasoning, I find that is unnecessary. Instead, I pan-sear the fish with a mixture of oil and butter, which works to keep the fish moist while seasoning the fish and keeps the dish a bit lower in fat and calories.
Oil: Use canola, avocado, or olive oil. The mixture of oil and butter will help keep the butter from burning.
Lemon: Fresh lemon juice is a MUST to finish the fish. It will add acidity, moisture, and flavor.

How to Make Blackened Mahi Mahi

In a small bowl, mix together the salt, paprika, garlic powder, onion powder, thyme, and cayenne pepper together.
Pat the fish dry with paper towels. This will help the seasoning blend to adhere to the fish, giving it so much flavor.

Sprinkle the cajun seasoning blend evenly over both sides of the fillets, rubbing the mixture into the fish with your hands to help the spice blend adhere to the fillets.

2 seasoned mahi mahi fillets with cajun seasoning.

Heat a large saute pan over medium-high heat and add the butter and oil. Once the butter is melted and the oil is hot, add the seasoned fish to the skillet, being sure to not overcrowd the pan.

Mahi mahi fillets iin skillet with butter and oil.

Cook, undisturbed, for 3 minutes, or until golden brown. Gently flip the fish over and continue to cook, undisturbed for an additional 3-4 minutes, or until the fish is browned on the opposite side, and opaque.

2 cooked mahi mahi fillets in skillet with parsley flakes.

Remove the fish from the skillet, and squeeze a wedge of fresh lemon over each fillet.

Blackened Mahi Mahi being scooped up on spatula.

Serving Suggestions

Serve the blackened Mahi Mahi with a side of cheesy grits and green beans almondine for a delicious, hearty meal.
Cut or flake the cooked blackened fish into small bite-size pieces and serve in homemade tortillas with pineapple mango salsa for an incredibly delicious and quick Mahi Mahi taco.
Serve the blackened fish on a homemade biscuit topped with coleslaw for an easy fish sandwich.

Blackened Mahi Mahi on plate served next to cheesy grits.

Storing Leftover Fish

Fish is best served immediately after preparation. However, if you happen to have leftover Mahi Mahi, store it in an airtight container in the refrigerator for up to 48 hours. Reheat in a dry skillet over medium heat for a couple of minutes per side, or until warmed through, and squeeze fresh lemon juice over the fish immediately before serving.

Recipe FAQs

What is the best way to defrost frozen mahi-mahi?

To defrost frozen fish fillets, either place the frozen fillets in the refrigerator overnight OR place the frozen fillets, still in the packaging in a bowl of cold water in the refrigerator. It will only take a couple of hours for the fish to fully defrost this way. You also can opt to run the frozen fillets under cold water until defrosted, but I find this method to defrost the fish a bit unevenly.

Is fresh or frozen Mahi Mahi best?

Nothing compares to freshly caught fish. However, unless you live next to the ocean, it is really hard to find super fresh mahi-mahi. I personally opt for frozen mahi-mahi, as I know it is frozen at its peak freshness and will taste fresh without a fishy taste or smell when cooking.

Can this be made dairy-free?

The butter will add incredible richness and help the exterior of the flesh to become golden brown. However, if you are dairy-free simply omit the butter and sear the fish in 2 tablespoons of heated oil.

Can I use another seasoning to make blackened fish?

Yes! Jerk seasoning or Old Bay seasoning are great alternatives to the cajun blend of spices.

More Easy Seafood Recipes

If you enjoyed this simple recipe for Blackened Mahi Mahi, I would love for you to leave a comment and review below.