In a pot on medium heat half filled with hot oil, add red snapper slices and fry until lightly golden. Set aside.
In a pot on medium heat filled with boiling water, add lemongrass, zucchini, tomatoes, eggplant, okra and basil. Turn heat down to low and simmer for 15 minutes.
Season to taste with fish sauce, then remove from heat.
Garnish with red snapper slices and serve hot.