In a wide bowl mix all of the dry spices for the spice blend and keep aside.
Cut the fish fillet into 4 pieces and then coat each piece with the seasoning, pressing & turning the fish gently in the spice bowl to coat all the sides.
Heat a cast-iron skillet or a nonstick pan over medium heat. Add oil and once it's heated, place the seasoned fish pieces on the pan. Depending on the thickness of the fish you can turn the fish in 2 to 4 minutes and cook on the other side for 2 to 4 minutes. Take the fish out and gently break it with a fork.
In a medium bowl mix pineapple, red pepper, jalapeños, and onion. Add cilantro, salt & squeeze fresh lime juice. Mix well.
To make the avocado cilantro sauce, add cilantro, avocado, yogurt, garlic, jalapeno & salt to the food processor. Squeeze lime juice. Blend until smooth.
To warm the tortillas you can cook them directly over medium flame until it gets a few charred marks. Use stainless steel pair of tongs to turn them over after 30 to 40 seconds.
To assemble the tacos, place a few spoonfuls of fish in the center of the tortilla. Top with pineapple salsa and cilantro avocado sauce. Serve immediately.
Any leftover fish, salsa, or sauce can be refrigerated for up to 2 days.
For a gluten-free meal, use corn tortillas or gluten-free tortillas
Substitute fish with shrimp for delicious blackened shrimp tacos
For a dairy-free option, use soy yogurt in the avocado cilantro sauce
Have a mango on hand? use instead of the pineapple and make mango salsa
Have a grill on? Cook your fish on the grill, over grill mat
Generously brush oil on the fish and bake it in the oven at 400 degrees for 10 minutes, then broil for 1 min for perfect blackening on the top