Blackened Mahi Mahi (Easy Cajun-Style Fish Recipe)
This Blackened Mahi Mahi recipe delivers tender, flaky fish coated in bold Cajun spices and pan-seared to perfection. It’s quick—just 15 minutes from start to finish—and topped with creamy avocado and fresh lime for a bright, balanced finish. Naturally paleo, Whole30, keto, and gluten-free, it’s a flavorful and healthy dinner that feels restaurant-worthy but couldn’t be easier to make at home.
Table of Contents
Why You’ll Love This Recipe
This recipe is a go-to when I want something quick, nourishing, and packed with flavor. The Cajun spice blend adds a smoky, savory kick, while the high-heat sear gives the fish a crisp, blackened crust without drying it out. The mahi mahi stays buttery and tender on the inside—so satisfying.
Topping it with sliced avocado adds creamy richness, and a generous squeeze of lime balances the heat with a burst of citrusy brightness. Whether you’re eating grain-free or not, it’s incredibly adaptable. I often serve it with cauliflower rice for a low-carb dinner or wrap it in tortillas for the best fish tacos. And if you’ve tried my Blackened Salmon or Halibut with Cauliflower Risotto, you’ll love this too.
Ingredients You’ll Need
- Smoked Paprika: Gives the signature blackened color and smoky-sweet depth essential to Cajun flavor.
- Garlic Powder & Onion Powder: Provide aromatic, savory backbone to the seasoning blend.
- Dried Thyme & Oregano: Add herby, earthy balance that complements the bold spice.
- Salt & Black Pepper: Brighten and sharpen the flavor without overpowering it.
- Cayenne Pepper: Brings heat—start small and adjust to taste. This is where the “blackened” magic happens.
- Mahi Mahi Fillets: A lean, firm white fish that holds up beautifully to high-heat cooking. Look for wild-caught mahi mahi (Costco has great frozen options). If frozen, thaw overnight and pat dry thoroughly before cooking for best texture.
- Coconut Oil: Ideal for searing thanks to its high smoke point and light tropical note. Avocado oil or olive oil also work well.
- Avocado & Lime Wedges: Optional for serving, but highly recommended! The cool avocado contrasts the spices, and the lime brings everything to life.
Step-by-Step Instructions
Step 1: Make the spice blend by combining all the dried spices on a plate or a small bowl and stirring with a fork to combine.
Step 2: Heat a medium-sized skillet (I used a large cast-iron skillet) over medium-high heat. While it is heating up, dredge the fish filets in the cajun dry rub, and coat evenly.
Step 3: When the pan is warm, add the coconut oil, and place fish on the hot cast iron skillet. Cook until cooked through. The cooking time will depend on the thickness of your fish fillets. Typically about 3-4 minutes per side. The fish is cooked when it flakes easily and reaches an internal temperature of 145 degrees F.
Step 4: Serve warm. Top with sliced avocado and wedges of lime. I love serving mine on top of my coconut lime rice or cauliflower mash.
Expert Tips
- Adjust the spice level by starting with ¼ to ½ teaspoon of cayenne if you’re spice-sensitive.
- Use any firm white fish if mahi mahi isn’t available—halibut, cod, or even salmon work beautifully.
- Grill it: Preheat the grill to medium-high, oil the grates, and grill for 3–4 minutes per side until cooked through.
Serving Tips
- Low-carb sides: Serve with Mashed Cauliflower or Cauliflower Rice.
- Classic rice pairings: Coconut lime rice or white rice make a delicious base.
- Mahi mahi tacos: Load into corn tortillas with slaw, mango salsa, and avocado for a summery twist.
Storage Tips
- Refrigerate: Store leftovers in an airtight container in the fridge for 3–4 days.
- Reheat: Gently reheat in a skillet with a splash of oil to keep it moist and crispy.
- Freeze: Wrap cooled fillets in plastic wrap and freeze in an airtight container for up to 3 months. Thaw in the fridge before reheating.
Recipe FAQs
Make sure your pan is hot and well-oiled before adding the fish. Also, pat the fish completely dry so the seasoning sticks and forms that crust instead of steaming.
It depends on the cayenne. As written, it has a mild to medium kick. You can easily adjust the heat by using more or less.
Yes! Bake at 400°F for 12–15 minutes on a parchment-lined baking sheet. It won’t get as crispy, but still tastes amazing.
Place it in the fridge overnight. Avoid quick-thawing in the microwave to prevent uneven texture. Once thawed, pat dry before seasoning.
If you’re looking for a fast, healthy, and flavor-packed dinner, this Blackened Mahi Mahi is the one to try. It’s got bold Cajun flavor, tender flaky texture, and comes together in just minutes.
More Delicious Seafood Recipes to Try!
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Blackened Mahi Mahi (Easy Cajun-Style Fish Recipe)
Ingredients
Blackened Cajun Spice Rub
- 1 teaspoon dried parsley
- 1 teaspoon dried oregano
- 1 teaspoon dried thyme
- 1 teaspoon smoked paprika
- 1/2 teaspoon cayenne pepper*
- 1/2 teaspoon onion powder
- 1/2 teaspoon garlic powder
- 1/2 teaspoon salt
- 1/2 teaspoon pepper
Blackened Cajun Mahi Mahi
- 2 6-oz wild caught Mahi Mahi** filets, thawed and patted dry
- 1 tablespoon coconut oil
- 1 avocado, sliced
- lime wedges for serving
Instructions
- Make the spice rub by combining all the dried spices on a plate and stirring with a fork to combine.
- Heat a medium size skillet over medium high heat. While it is heating up, dredge the fish filets in the spice rub and coat evenly. When the pan is warm, add the coconut oil, and cook the spice rubbed fish until cooked thru. Cooking time will depending on the thickness of your fish. Typically about 3 to 4 minutes per side.
- Serve warm. Top with sliced avocado and wedges of lime. I love serving mine on top of my coconut rice.
Notes
Expert Tips
- Spice Level: 1/2 teaspoon cayenne pepper will make this mild spicy. If you like it spicier, feel free to add more. If you are heat sensitive, add less or even leave it out so it is more kid-friendly.
- Fish Alternative: This recipe will work for any firm fish filet. I’ve also done this with halibut, salmon, and sole. Use any wild-caught fish of your choice!
Serving Tips
- If you have the time and it works with your diet, I must insist you make my coconut lime rice to go along with this. All of the flavors together are just too good!
- For a low-carb option, serve with cauliflower rice or mashed cauliflower.
Storage Tips
- Store leftovers in an airtight container for up to 3 days. Reheat over the stovetop in a skillet with a bit of oil until the fish is warmed through.
- To freeze, wrap the cooked and cooled fish tightly in plastic wrap. Then place it into a freezer-safe container. Store for up to 3 months. Thaw and reheat over the stovetop. If stored any longer, cooked fish can have a strange texture, so be sure to eat it within 3 months.
32 Comments on “Blackened Mahi Mahi (Easy Cajun-Style Fish Recipe)”
Delicious with the coconut lime rice.
Love to hear this!
Never get tired of this. It’s delicious!
Thank you! Means so much to me!
Love it. Make it all the time. :)
I am so happy you like this and it has made it into your recipe rotation Colleen.
Just made!! Good flavor and quick to prepare. I am missing the advocado ( wasn’t on hand) but I can tell it would have been a nice finish to the Cajun flavor. I pared with couscous and fresh steamed kale!! Will surly make again soon! ( like this week with the advocado)
So glad you liked it Tiffany!
This turned out delicious. I plan to make it again – thanks for sharing!