Wash the fish fillet, pat dry and cut into cubes. Drizzle with the lemon juice, then season with salt and pepper.
Clean and wash the fennel and carrot and cut into fine strips. Peel the ginger, chop it finely and sweat it in hot olive oil. Add the fennel and carrot and fry briefly. Pour in the broth and cook for approx. 15 minutes. Add the fish fillet to the soup and let it simmer for 5 minutes. Season to taste with soy sauce, salt and pepper. Finally add the coriander greens.