Finely chop the garlic and cut the tomatoes into wedges. Cut the lemon into thin slices and the fennel into fine strips. Pour boiling water over the couscous and let it steep.
Sweat the fennel in the olive oil, add the garlic and sweat briefly. Add the tomato wedges and fry for about 5 minutes. Season with salt and pepper, deglaze with vinegar and wine.
Place the halibut on top of the tomatoes, season with salt and pepper. Spread the lemon slices on the fish and put the lid on the pan. Cook on medium heat for 8-10 minutes.
Serve everything on the couscous. Green salad and white wine go very well with it.