Wash the catfish with salt and vinegar, use a knife to scrape off the black skin until it's no longer slimy, then rinse clean. Marinate the fish with chopped onions, garlic, oyster sauce, and a pinch of salt. Clean the bean sprouts, taro stem, tomatoes, okra, green onions, and cilantro. Cut the tomatoes into wedges, slice the okra and taro stem diagonally, and chop the pineapple into small pieces.

Sauté the onions and garlic until fragrant, add the fish and sear it on all sides to firm up the pieces, then pour in boiling water (cold water will make the fish smell fishy), and add a bit of rock sugar.