In separate pot, simmer 3 (7 oz.) catfish fillets in 1 quart of lightly salted water for 15 minutes. Strain through cheese cloth and reserve liquid. Chop catfish and reserve meat. In heavy bottom gumbo pot, add oil and flour. Cook over medium high heat stirring constantly until golden brown. Caution, do not scorch!
Add all seasonings except green onions tops. Saute for 5 minutes. Add all fish stock and chopped catfish. Add hot water, one ladle at a time, until consistency of thick soup is achieved. Add claw crab meat, and half of shrimp. Reduce to simmer. Cook approximately 45 minutes, stirring occasionally. Add catfish, remaining shrimp and green onions tops. Cook 10-15 minutes. Season to taste using salt and cayenne pepper. Add water if necessary to retain volume. Serve over white rice.