Blackened Mahi-Mahi with Homemade Seasoning

Name: Blackened Mahi-Mahi with Homemade Seasoning
Prep time: 10 min
Cook time: 10 min
Total time: 20 min
Ingredients: 12 ounces Mahi-Mahi; 1 tablespoon paprika; 2 teaspoons onion powder; 1/2 teaspoon garlic powder; 1/2 teaspoon ground black pepper; 1/2 teaspoon salt; 1/2 teaspoon cayenne pepper; 1/4 teaspoon dried oregano; 1/4 teaspoon dried thyme; 3 tablespoons extra virgin olive oil or coconut oil

By Marley Goldin

on May 2, 2021

5 from 2 votes

This post may contain affiliate links. Please read my disclosure policy.

This healthy Blackened Mahi-Mahi strikes the perfect balance of herbaceous, smoky, and spice to get you a nutritious dinner in just 20 minutes!

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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!

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 along with roasting it.

blackened fish with a bite cut off and on a fork

Blackened Mahi-Mahi Tips and Tricks

The Blackening Seasoning

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.

thyme, paprika, garlic powder, salt, oregano, cayenne pepper, onion powder, black pepper

Fresh or Frozen

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.

This spice blend and technique will also work for almost any white fish including cod, flounder, halibut, and sole! The blackening technique is also incredible to use for Blackened Ahi Tuna.

Green tip: Despite recycling efforts, the sad truth is that only about 9% of plastics are recycled, leaving the rest to become microplastics. Reduce your contribution to plastic waste by using these reusable plastic bags (affiliate link).

Make Sure To 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.

drying fish with a paper towel next to bowl of spices

Get a Thick Coat

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.

raw fish filets coated in blackening seasoning

Get Your Oil Hot

I highly recommend using a cast-iron skillet to get your Mahi-Mahi perfectly blackened. I use this Lodge cast-iron (affiliate link) 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.

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.

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).

Doubling the 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.

Green tip: Did you know that of the billions of pounds of food wasted annually, it is estimated that 50% of it happens in our homes. It’s always best to avoid food waste as much as you can! That means storing your leftovers properly so you can eat them later!

Should You Have Leftovers

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

Sustainable Seafood

Mahi-Mahi is generally considered a sustainable fish to eat as it is fast-growing and has a short life cycle. They are generally caught from marine fisheries (not fish farms) utilizing longlines which means little to no bycatch!

Green tip: The most sustainable way to eat Mahi-Mahi is to look for U.S. Atlantic Mahi-Mahi.

overhead shot of blackened fish resting on greens

Why You Should Make this Blackened Mahi-Mahi

It’s quick! Less than 20 minutes will have this on the plate!
It’s flavorful. The punch of flavor from the seasoning and the smoky blackened exterior is incredible.
It’s healthy! Mahi-Mahi is a great source of lean protein and a number of vitamins and minerals.

Looking for something to serve this Blackened Mahi Mahi with? It’s incredible with this Saffron Rice and Garlic Lemon Asparagus.