Step 1) Slice catfish into 1-inch thick portions. Bring fish stock or clam juice to a boil in a large stock pot over medium high heat; add catfish and boil for 5 minutes. Reduce heat and add pineapple, star anise, crushed red pepper, okra and lime juice; simmer 5 minutes. Stir in bean sprouts, tomato wedges, fish sauce and sugar. Keep soup warm over low heat. Remove star anise before serving.