Season fish fillets. Heat oil and lightly sear fillets. Remove from skillet.
In the same skillet place onion and cook until soft but not colored. Add tomatoes and cook 2 to 3 minutes more.
Place fish on top of onions and pour soy sauce. Cover skillet and let fish finish cooking.
Two or three minutes before fish is ready add snow peas and cover again. Finish cooking fish and serve immediately.
How to fillet, skin and debone fish