In a pot combine leeks, onions, fennel, shallots, bay leaf, coriander seeds, white pepper and fish bones. Add just enough water to cover. Bring to a boil and let simmer for 45 minutes. Strain through a fine chinois.
In a casserole sweat celery, leeks and whole garlic in 2 ounces virgin olive oil and 2 ounces butter until both are softened but still have some texture, about 6 or 7 minutes. Add beans,thyme and salt and pepper to taste.
Season sea bass fillets with salt and pepper. In a large saute pan, heat oil and add fillets. Sear on both sides and finish in oven, if necessary. Garnish with confit tomato and young celery leaves