Heat a teaspoon of olive oil in a frying pan over medium-high heat. Sprinkle salt and pepper and lemon juice over the fish and cook for 5 minutes on each side until translucent and flaky.
Meanwhile, in another frying pan, heat remaining oil over medium-high heat. Add the onion, courgette, tomatoes salt and pepper and sauté until tender.
Serve the fish with a drizzle of lemon juice with the vegetables on the side.