Blackened Mahi-Mahi – Elevate boring fish fillets by coating them in butter and warm homemade Blackening Seasoning. Pan sear the fish over high heat for mahi-mahi that’s crisp on the outside and moist and flaky on the inside. Eat as is, or garnish with our fresh Mango Salsa.

WHAT IS BLACKENED MAHI MAHI?
Mahi-mahi is a healthy Hawaiian fish packed with protein and nutrients. We coat the fillets in butter and blackened seasoning before searing them in a hot cast-iron skillet to create a beautiful, tasty crust that’s the perfect balance of herbaceous and smokey. Blackening is a Cajun cooking technique to prepare fish, vegetables, and meat. While it may look burnt at first glance, that color means flavor and lots of it!
WHAT YOU NEED TO MAKE THIS RECIPE
- Mahi-Mahi: Mahi mahi is naturally sweet and mild, and it pairs perfectly with the robust flavor of the blackened seasoning. I use frozen wild-caught mahi-mahi filets from Costco most. However, if you have access to fresh fish, use that instead.
- Butter: Butter binds the blackened seasoning to the fish fillet.
- Blackened Seasoning: Take a moment to check out the Blackened Seasoning. Ours combines American chili powder, garlic powder, oregano, smoked paprika, cumin, salt, pepper, and cayenne pepper for a bit of heat. If heat is a concern, consider omitting the cayenne.
HOW TO MAKE BLACKENED MAHI MAHI
Salt the defrosted filets and let them sit for 5 minutes.

Pat dry the fillets to remove any moisture.

Lightly coat them with melted butter using a pastry brush.

Combine the ingredients for the Blackened Seasoning in a small bowl and generously cover both sides of the fish.

Warm avocado oil in a cast-iron skillet over medium heat until it begins to smoke.

Once heated, carefully add 1-2 filets to the pan to cook for 3-4 minutes on each side. Cooking time may vary depending on the thickness of the filet. Repeat with the remaining filets (see note).


Garnish with fresh lemon and serve with salad, rice, or pilaf.

COOKING TIPS
- The key to a well-seared fish is a well-coated, hot pan. Warm a cast-iron skillet on medium and give it time to heat up before cooking the fish.
- Mahi-mahi is versatile and cooks well, but it’s still a lean fish; they will dry out if they overcook, and no one wants that.
- How do you know when the fish is done cooking? When the fillet easily releases from the pan, it is done cooking. If it sticks, it’s not quite ready. Give it more time. Use a food thermometer to check the temperature; the safe internal temperature for mahi-mahi is 137° F (58° C).
- Speaking of hot- there could be a lot of smoke!! Do yourself a favor and turn on your exhaust fan. I often remember when it’s already too late.
SEARCHING FOR MORE LIKE THIS?
If you love this recipe, try one of these tasty seafood-centered meals!

FRESH OR FROZEN FILETS?
I’ve lived in landlocked states my whole life, so I am a big fan of frozen fish, especially mahi-mahi. The key to using frozen fish for this recipe is setting aside time for the fish to thaw properly. The best way to defrost mahi-mahi is to transfer it from the freezer to the fridge and leave it there overnight.
If you’re in a hurry, add frozen fillets to a sealed bag (Costco filets have individual wrappers), and add them to a mixing bowl with cold water for about 10-15 minutes. If you have access to fresh fish, go for it!
SERVING SUGGESTIONS
- Rice, Pilaf, Risotto, Quinoa, Brown Rice
- Grilled Zucchini, Mixed Greens
- Red Beans and Rice
- Vegetable Chopped Salad
WHAT TO DO WITH THE LEFTOVERS
- TO STORE – After you’ve blackened the mahi-mahi, eat them within four days.
- TO FREEZE – Cooked fish freezes for 2 months. Wrap the fillets tightly in plastic wrap and place them in a freezer-safe bag or container. When you’re ready to eat it, defrost it in the fridge overnight.
- TO REHEAT – Line the fillets onto a rimmed baking sheet and cook in a preheated oven to 275° F (135° C). Cook for 15 minutes.
- TO REPURPOSE – You can serve leftovers with fresh Mango Salsa; that’s our favorite. Break up the cooked fish and add it to a corn tortilla to make blackened mahi-mahi tacos. Top them with Pico De Gallo or Serrano Crema. Serve the fish with pilaf, or mix it with rice and black beans for a fun spin on a burrito bowl. Blackened mahi-mahi is the perfect protein to add to any Vegetable Chopped Salad! Make a blackened mahi-mahi sandwich using avocado, cabbage, butter lettuce, and spicy mayo dressing on a fresh ciabatta bun.
FREQUENTLY ASKED QUESTIONS
How do you know when the fish is done cooking?
You will know the fish is done cooking when it easily releases from the pan. If it sticks, it’s not quite ready. Give it more time. Use a food thermometer to check the temperature; the safe internal temperature for mahi-mahi is 137° F (58° C).
How do you cook mahi-mahi in the oven?
Prepare a rimmed baking sheet with a wire rack, and give it a quick spray with avocado oil. Line the fish onto the wire rack and bake at 375° F (190° C) for 8-10 minutes. Use a food thermometer to check the temperature of the fish; the safe internal temperature for mahi-mahi is 137° F (58° C).
How do you grill blackened mahi-mahi?
Prepare the grill and set the heat to 375° F (190° C). Cook the fish in a cast-iron skillet- the same way you would in an oven. Since every grill is different, I suggest checking the temperature and fish at the 4-minute mark.
YOU SHOULD ALSO TRY:

Blackened Mahi-Mahi
Equipment
- Small Bowl
Ingredients
- 5 Filets mahi-mahi
- 1 tablespoon butter, melted
- 2 tablespoons avocado oil
- ½ cup blackening seasoning
Instructions
- Salt the defrosted filets and let them sit for 5 minutes. Then, pat them dry with a towel to remove excess moisture.
- Lightly coat them with melted butter using a pastry brush.
- Combine the ingredients for the blackened seasoning in a small bowl and generously cover both sides of the fish.
- Warm avocado oil in a cast-iron skillet over medium heat until it begins to smoke.
- Once heated, carefully add 1-2 filets to the pan to cook for 3-4 minutes on each side. Cooking time may vary depending on the thickness of the filet. Repeat with the remaining filets (see note).
- Garnish with fresh lemon and serve with salad, rice, or pilaf.
Notes
- The key to a well-seared fish is a well-coated, hot pan. Warm a cast-iron skillet on medium and give it time to heat up before cooking the fish.
- Mahi-mahi is versatile and cooks well, but it’s still a lean fish; they will dry out if they overcook, and no one wants that.
- When the fillet easily releases from the pan, it is done cooking. If it sticks, it’s not quite ready. Give it more time. Use a food thermometer to check the temperature; the safe internal temperature for mahi-mahi is 137° F (58° C).
- Speaking of hot- there could be a lot of smoke!! Do yourself a favor and turn on your exhaust fan. I often remember when it’s already too late.
- The nutritional information shown is an estimate provided by an online nutrition calculator. It should not be considered a substitute for professional advice.
- Check out our web story for pan-seared blackened mahi-mahi!
TW
Wednesday 8th of June 2022
The rub for this fish is amazing! I want to put it on everything. I am trying it on chicken next!
Tressa Jamil
Sunday 12th of June 2022
We actually have a blackened chicken recipe coming out soon and that's exactly how we did it!
Kristine Corey
Monday 7th of March 2022
Love this recipe, will have to try the mango salsa too!
Tressa - Jamil Ghar Team
Sunday 13th of March 2022
Hey, thanks for commenting! You'll have to let us know what you think of the mango salsa when you're able to try it.