Heat 2 ounces of the olive oil in a medium pot over medium heat.
Add the onion and pepper and sauté them until the onion begins to get tender, 3 to 5 minutes. Add the garlic and continue to sauté the vegetables for an additional 2 minutes. Add the okra and sauté for approximately 3 to 5 minutes. Add corn and sauté for 3 minutes more.
Increase the heat to medium-high
Add the chicken stock, tomato, and tomato puree. Bring to a strong simmer. Reduce the heat to low.
Add the cayenne pepper. Season to taste with salt and black pepper. Cook for 10 minutes.
Add catfish and cook for an additional 10 minutes until fish is cooked. Add the crab meat.
Place the pot over medium heat and cook the stew for an additional 5 minutes to ensure catfish is fully cooked and crab is warmed through.
Add the green onion and cook for an additional 3 minutes. Add parsley. Adjust the seasoning with salt and pepper if needed.
Serve over steamed rice or grits, if desired.