Rinse sea bass briefly and dab dry. Fillet the fish, cut off the head and put aside. Cut the fillets in half crosswise and cover and chill. Remove the skin from the squid. Remove heads and chitin strips (whalebone) from the inside.
Wash out with cold water, dab dry very well. Cover the tubes and tentacles and place them in a cool place.
For the lobster sauce, peel and chop the shallots and garlic, except for 2 cloves. Heat 100 ml oil. Fry fish head, shallots and garlic in it. Deglaze with white wine and stock. Add lobster soup and simmer for 30-40 minutes, about halfway through.
Skim off any foam produced in between.
Clean or peel, wash and chop the soup greens. Bring 1 l water with soup vegetables, bay leaf, 2 tsp salt and 1 tsp peppercorns to the boil. Simmer for about 10 minutes. Pour the stock through a sieve into a pot.
Wash the potatoes thoroughly, cut them into slices with the skin on. Crush 2 cloves of garlic. Wash the thyme. Add potatoes, garlic and thyme to the vegetable stock you have collected, bring to the boil and cook the potatoes in it for 15-20 minutes over medium heat.
Cook the squid tubes and squid catching arms for about 5 minutes.
Wash the basil and shake it dry, put some leaves aside. Coarsely mortar 1 tsp. peppercorns. Switch off the stove. Add lemon zest, juice, basil and pepper to the lobster sauce. Leave to stand for about 5 minutes.
Pour the stock through a fine sieve into a pot. Gradually add 100 g cold butter in flakes and mix with a hand blender. Drain potatoes and squid, drain and add to the lobster sauce.
In the meantime, place the fish fillets in a cold pan with 50 g butter and 2 tablespoons of oil. First fry on the skin side for 2-3 minutes. Then turn and fry on the other side for about 2 minutes. Season with salt.
Cut the rest of the basil into fine strips and the chives into wide rolls. Arrange the squid sauce with fish fillets and sprinkle with herbs.