Blackened Mahi Mahi is a savory seafood dish that you can throw together in less than 15 minutes. It’s both healthy and tasty! With a delicious Cajun seasoning blend seared into a crispy, spicy crust, the textures and flavors are simply out of this world.

Blackened mahi mahi is an excellent meal any day of the week. This flaky Hawaiian fish is actually tremendously healthy, with plenty of lean protein and vitamins.
Cooking mahi mahi doesn’t take much time at all. However, you should know — this is a rather smoky process! Keep your kitchen well ventilated while cooking.
Between the paprika, pepper, and ginger, this dish has a great level of heat and spice, and the Cajun spice blend forms a delicious blackened crust. Serve with slices of lemon on a bed of fluffy white rice or alongside crisp or roasted vegetables.
This seasoning blend actually tastes great on all kinds of seafood! I recommend trying it out with more of your favorites. My Pan Seared Ahi Tuna and Shrimp recipes, in particular, taste extraordinary.
I also have just the thing for Marylanders who can’t get enough of that Old Bay taste — my Old Bay Substitute!

INGREDIENT NOTES AND SUBSTITUTIONS
- Mahi Mahi – While it isn’t too fishy, it does have a distinctive flavor that could be described as sweet. It also has a firm texture that flakes deliciously when fried.
- Butter -When blackening fish, you want to fry in melted butter to help quickly form the seasoned crust. I wouldn’t recommend using oil for this recipe.
- Blackened Fish Seasoning -My Cajun seafood seasoning blend is versatile and can be used on almost anything. In addition to salt and black pepper, it contains:
- Paprika – A versatile spice with a mild, smoky heat that can be used to season any protein.
- Cayenne – This pepper has an iconic heat that is held in high esteem by spice lovers. Use it to spice up any dish.
- Ground Ginger – Ginger adds another layer of spice, though it is not as severe as the peppers we use. It is also slightly sweet and goes well with seafood.
- Oregano – Bitter and peppery, this has a distinctly earthy flavor.
- Fennel Seeds – This seasoning is unique and is often paired with oregano and cloves. Also earthy, though more mild and warm.
- Ground Cloves – Sweet and rich, with a hint of bitterness.

HOW TO MAKE BLACKENED MAHI MAHI
- Prepare the Fish. Rinse lightly in running water. Pat dry with paper towels and dispose of the paper towels immediately to avoid spreading bacteria in your kitchen.
- Mix the Spices. Combine the Cajun seasonings in a small bowl and set aside.
- Heat the Skillet. Don’t add butter just yet! Heat the pan over high heat until it begins to smoke.
- Season. Smother the fish with melted butter and then dust with the seafood seasoning blend. Press the spices onto the filet to form an even crust and to help it stick.
- Sear. Carefully place the filet in the hot pan and cook for 2-3 minutes on each side, until a dark crust forms and the center is cooked through.
- Serve. Plate and serve immediately over a bed of fluffy steamed rice with fresh lemon.

How do you know when mahi mahi is done?
Any fish will flake easily when cooked thorough and go from translucent to opaque. When cooking mahi mahi, you may want to use a kitchen thermometer. Insert the probe at an angle into the thickest part of the filet — when it reads around 135°F, it’s done! The temperature will continue to rise a few degrees as it rests.
What does it mean to “blacken” a fish when cooking?
“Blackening” a fish just means to quickly sear it on either side. Frying at a high heat creates a crispy outer layer to contrast the flaky inside. It’s delicious, quick, and easy!
What is the best way to prepare mahi mahi?
I’m partial to blackened mahi mahi, prepared by frying in butter. It takes about 15 minutes to prep and fry a 1 pound filet. When seared, you get an incredible seasoned crust and perfectly flaky fish in the quickest amount of time. Alternatively, you could grill for 4 minutes on each side. If you prefer to bake your filet, then set your oven to 375°F and bake for 8 minutes.
How long can I keep mahi mahi in the refrigerator?
Don’t refrigerate raw fish for longer than two days. Once the blackened mahi mahi is cooked, it should stay good for up to 4 days. To reheat, bake at 325°F for just a few minutes. I wouldn’t recommend reheating on the stove, as it dries out fairly easily.

Other fantastic blackened dishes include:
- Pan Seared Blackened Ahi Tuna
This is tastefully seasoned with blackened Cajun spices and served up with steamed leftover barley and salad. - Blackened Filet Flatbread Melts
Cubed beef filet tossed with butter and blackened seasonings, fresh vegetables cooked on flatbread with cheeses. - Blackened Ahi Tuna Vegetable Soup
A savory vegetable soup topped with some blackened ahi nuggets.
For another blackened seasoning, try my Blackened Meat Seasoning. Enjoy!
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Blackened Mahi Mahi
Ingredients
- 1 lb fresh mahi mahi
- 2 1/2 tsp blackened fish seasoning (See below recipe)
- 1/4 cup melted butter
Blackened Fish Seasoning
- 1 tsp paprika
- 1/2 tsp salt
- 1/2 tsp cayenne pepper
- 1/4 tsp ground ginger
- 1/4 tsp black pepper
- 1/4 tsp oregano
- 1/4 tsp fennel seeds
- 1/8 tsp ground clove
Instructions
- Rinse the fish and pat dry with paper towels.
- In a small bowl mix together the spices and set aside.
- Place a frying pan or cast iron skillet over high heat until it starts to smoke. Keep kitchen area well ventilated.
- Toss the mahi mahi in melted butter and then coat with spice mixture on both sides. Press spice mixture to adhere.
- Immediately sear on high heat 2-3 minutes per each side or until desired doneness is reached and center is cooked. Don’t overcook as it will dry out. Serve immediately with slices of lemon and steamed rice.
Notes
The information shown is an estimate provided by an online nutrition calculator. It should not be considered a substitute for a professional nutritionist’s advice.
Nutrition

I love blackened anything and this blackened seasoning works with almost everything but this fish was outstanding. Crispy, tender and delicious.
Going to give it a try tonight. My only problem with the recipe is that all my old salty fishermen buddies have always told me never NEVER rinse salt water fish with fresh water. They said it ruins the fish and have to follow their lessons as they have been fishing and grilling for 40+ years. I have never tried to blacken it so super excited, thanks for the recipe!
How did it turn out Tomas?
My OH, mother, brother, and I all loved this!
I am so glad! We love it at our house too!
I order Mahi Mahi in restaurants all the time and have no idea why I never make it at home? Your blackened version has me inspired to do it immediately!
Super easy and delivers on flavor. Enjoy Marissa!
Blackened mahi happens to be one of my favorites Kevin! And I’m quite lucky because my husband Tom and several of our friends catch it fresh off and on all summer! Can’t wait to try your recipe!
Oh boy, you have all the luck Mary Ann. What I love about fish dinners is they are so quick and typically easy to prepare and never fail to leave me smiling.