First, heat the oil in a large pan over a medium-high heat. Be sure to heat the oil until pan is hot so the fish cooks quickly and is evenly browned. Meanwhile, season the fish fillets with taco seasoning until well-covered as this is how the fish gets all of its flavor.
Next, once the oil in the pan is hot, add the fish fillets to the pan and cook for a few minutes on each side until browned or blackened. The fish is done once it can be easily flaked with a fork. Then carefully remove the fish from the heat and break it up into small pieces and place on a plate.
Slice the lettuce among the bowls you are using to serve the salad. Portion out and add the cooked black beans, salsa, avocado, and sour cream. All of these ingredients are what make this fish salad a taco salad.
Finally, serve the fish taco salad with fresh lime wedges and cilantro, if preferred. You can even serve the salad with crispy tortilla strips or chips.