Heat olive oil in a frying pan and sauté onion and peppers for 3 minutes.
Add garlic, aubergine, and courgettes, then fry for 3 minutes while stirring.
Stir in the tomatoes and cook for one additional minute.
Incorporate basil and season with salt and pepper to taste.
Boil shallots, vinegar, and 60ml wine in a saucepan until 2 tablespoons of liquid remain.
Add 15ml water and simmer until only 1 tablespoon of liquid is left.
Whisk in 225g of butter a little at a time over low heat.
Strain the sauce into a clean pan, season, and stir in the chives.
Preheat the oven to 200°C and season the fish fillets.
Fry fish skin-side down in 50g foaming butter for 2 minutes before turning and adding 75ml wine.
Cover with a cartouche and bake for 4 minutes until the flesh is opaque.
Rest the cooked fish for 2 minutes before plate assembly.
Serve fish on top of ratatouille and drizzle with the chive sauce.