Crispy Blackened Mahi-Mahi (20 Minutes!)

Looking for a quick and flavorful way to prepare your fish? This Blackened Mahi-Mahi recipe teaches you how to make your own blackening seasoning and how to fry it up to get that crispy outer layer of smoky and spicy perfection!

This simple pan-fried fish recipe boasts tons of flavor and requires just 20 minutes to make, a must for a busy mom with a gourmet palate like me!

The best thing is you can use this same spice blend and technique for any white fish! Blackening is one of my favorite ways to prepare my fish because it’s guaranteed to bring bold flavor (see also: Blackened Cod).

Blackened Mahi-Mahi Ingredient Highlights

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This recipe is intended for individual portions of fresh skinless mahi-mahi, about 4-6 ounces per portion. If you’re using frozen mahi-mahi, make sure to thaw it before following this recipe.

I like using olive oil or coconut oil, but truly any oil will work here.

Adjust the amount of cayenne pepper according to your desired spice level! I use ½ teaspoon and find it to be moderately spicy. If you are sensitive to spice, use less, and if you really wanna kick it up you can add even more.

Fresh vs Frozen Mahi-Mahi

This recipe works great for either fresh or frozen fish, so long as it’s thawed properly. The best way to thaw out frozen fish is to transfer it from the freezer to the refrigerator the night before you’re ready to eat it.

If you need to thaw it more quickly, you can seal it completely in a plastic bag, and soak it in room-temperature water for about 15 minutes.

Mahi-mahi itself has a very mild flavor and meaty texture, making it the perfect blank canvas for your blackening seasoning.

The seasoning is a combo of herbaceous, spicy, and salty. Blackening infuses smokiness, too.

Blackened Mahi-Mahi Tips and Tricks

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How I Make Blackening Seasoning

Blackened fish refers to any fish cooked using a blackening technique. The blackening technique is when you coat your food with a blend of spices and then cook it on a very hot pan (typically cast iron) until the spices turn black and form a crust.

This blackening seasoning blend is designed to have a little bit of a kick—I would call it moderately spicy. If you like a lot of spice, kick your cayenne up a notch. If you’re here for the smoky, but not so much the spicy, you can choose to leave the cayenne pepper out altogether.

The spice blend utilizes all dried spices, but you are welcome to use fresh herbs like oregano and thyme if you prefer. Just make sure you dice them up very finely.

This spice blend and technique will also work for almost any white fish including trout, flounder, halibut, and sole! The blackening technique is also incredible to use for other fish like this blackened cod.

Make Sure to Pat Dry Your Mahi-Mahi

Whether you’re using fresh or frozen, it’s best to completely dry off your fish before coating it in the spice blend.

The easiest way to do this is by placing your fish filets in between two paper towels and pressing down. Drying the fish will ensure your seasoning blend sticks and will avoid any extra hot oil splatter from additional water on the fish.

Get an Even Layer of Seasoning on the Fish

Once you’ve dried your fish filets, add them to a shallow bowl with your blackening seasoning. Make sure to completely coat both sides of the fish with the seasoning.

Think of it almost as a breading. The seasoning will actually blacken and give you the crispy exterior with tons of smoky, complex flavor.

Get Your Oil Hot before Adding the Mahi-Mahi to the Pan

I highly recommend using a cast-iron skillet to get your Mahi-Mahi perfectly blackened. I use this cast-iron skillet and get that crispy blackened exterior every single time!

If you don’t have a cast iron skillet, a frying pan will do! Make sure you have a cover handy to stop any oil from splattering out and burning you.

Add your coconut or olive oil to the pan—you should have enough to coat the pan completely. Turn your stove up to medium heat and wait a minute or so for your oil to heat up.

Quick note: While handling raw fish, it’s important to make sure you wash your hands frequently and use a clean plate to transfer your cooked fish to (never re-use the plate the raw fish was resting on without washing with soap and water first).

You should hear a sizzling sound when you drop your fish into the oil. Immediately cover to avoid any hot oil splatter. Cook for 5 minutes and then check if it’s ready to flip.

You’ll know your fish is ready on that side because it will easily peel away from the skillet. If it’s stuck, it’s not quite ready. Give it another minute over medium before checking again.

Serving Your Blackened Mahi-Mahi

This Blackened Mahi-Mahi carries a lot of strong flavors and is best with milder sides like these Simple Roasted Potatoes or these Creamy Boursin Mashed Potatoes.

It’s also delicious with roasted veggies, over rice, between two buns in a sandwich, or in fish tacos!

How to Double this Spicy Mahi-Mahi Recipe

The seasoning should fully coat two 6-ounce servings of Mahi-Mahi, with little to no leftover seasoning.

You can choose to double or even triple the seasoning recipe if you want to have more blackening seasoning on hand to make another time. If you seal the seasoning, it can last for months, or even years, depending on the age of the ingredients you use.

If you’re cooking more than two servings of fish, go ahead and double the seasoning recipe, and pour it over the fish, instead of dunking the fish into it. Once the seasoning has touched the raw fish, it is no longer save-able.

How to Properly Store and Reheat Mahi-Mahi Blackened

Cooked Mahi-Mahi will be safe to eat if covered and stored in the refrigerator for another 3-4 days after preparation. The best way to reheat it is to cover it and place it in your preheated oven at 275 °F, for about 15 minutes or until the internal temperature reaches 145°F.

You can also opt to freeze your blackened mahi-mahi for up to 3 months. Just make sure to allow it to thaw overnight in the refrigerator before following the reheating directions above.