Prepare the fish and vegetables. Clean and cut the snakehead fish into chunks. Chop the vegetables and set aside.

Heat oil in a pot over medium heat. Add garlic, shallots, lemongrass, and kaffir lime leaves. Sauté until fragrant.

Add Thai chili paste and shrimp paste to the pot. Stir well to combine with the aromatics.

Pour in water and bring to a boil. Add fish sauce, palm sugar, and tamarind paste. Stir until the sugar dissolves.

Add the fish chunks and vegetables to the pot. Simmer until the fish is cooked through and the vegetables are tender.

Stir in Thai basil leaves just before serving. Adjust seasoning if necessary.