Clean the fennel, rinse and put some fennel green aside for garnishing. Cut the fennel into fine strips.
Peel the grapefruit and orange. Fillet the fruit over a small bowl, collecting the juice. Mix the juice with lemon or lime juice and honey. Season to taste with a pinch of salt and some freshly ground white pepper.
Cut the avocados in half and remove the seeds. Peel the halves and cut the flesh into thicker slices.
Arrange the prepared ingredients decoratively on a slightly deeper plate and sprinkle with marinade. Serve garnished with fennel green.