Clean fish from bones and cut into 1″ chunks, at an angle, and lightly dredge with flour.
Heat oil in wok over medium heat (or any pot). When hot, fry fish and cook until golden brown.
In the meantime, pound red spur chili, small hot chili’s and garlic into a paste in a mortar, set aside.
Bring vinegar, water, salt and sugar to a boil and lower heat to simmer until sugar has dissolved well.
Heat oil in wok and add garlic paste mixture and cook for a minute then add vinegar mixture and chicken stock and stir well. Cook for a minute.
Add as much corn flour slurry to lightly thicken the sauce, if needed.
Add basil leaves and stir well for 10 seconds and pour over fried fish.