1. Wash fish, pat dry, and cut into 2 x 2 cm pieces.
2. Mix fish
with starchflour, soy sauce and pepper and set aside.
3. Cut onions into
rings, cut tomatoes into bite size pieces.
4. Heat oil in a wok
or a pan and add fish.
Fry fish for 3-5 minutes, take out of the wok and set aside.
5. In the wok stir-fry
onion and add tomatoes. Add fish and stir well.
6. Add white vinegar,
fish sauce, sugar and ketchup and heat.