In a small bowl, combine the smoked paprika, garlic powder, onion powder, dried thyme, dried oregano, cayenne pepper, sea salt, and black pepper to create the Cajun rub.
Pat the catfish fillets completely dry with paper towels, then generously coat both sides of the fish with the spice mixture, pressing it in so it adheres well.
Heat the avocado oil in a large cast-iron skillet over medium-high heat until the oil is shimmering and just starting to smoke.
Carefully place the catfish fillets in the hot skillet and cook for 3 to 4 minutes per side, until the crust is dark and charred and the fish flakes easily with a fork.
While the fish rests, toss the warm cooked jasmine rice with fresh chopped parsley, lemon juice, and lemon zest until well combined and fragrant.
Serve the blackened catfish immediately over the bed of lemon-herb rice, garnished with extra lemon wedges if desired.