Heat the oil & butter. Next, preheat the Blackstone grill to medium-high heat and add the canola oil. Spread it in an even layer with a long-handled spatula.
Cook on the griddle. Place the filets on the hot grill and cook on each side for about 3-4 minutes, until the fish flakes easily with a fork and is a light golden brown color.
You can also blacken catfish in a cast-iron skillet on your gas grill! * Preheat a large cast-iron skillet over medium high heat on the grill. * Add oil and butter and heat until foamy.* Cook the catfish on each side for 3 minutes, until it flakes easily with a fork.