Prepare the chermoula marinade and wash & marinate the fish for at least 2 hours or even better overnight.
Peel and slice the tomato, then slice the onion and bell pepper into rings.
Peel, wash and slice the potatoes then combine the ginger, salt, pepper, turmeric and some olive oil, coat the potato slices in it and set aside.
In a tagra pot, oven or casserole dish, brush the base with some olive oil and smother with some chermoula marinade.
Layer the marinated base with sliced tomato and onion rings, followed by a layer of sliced potato.
Top the potato layer with all the fish pieces and all its juice and marinade, then cover the fish with the peppers and any remaining vegetables.
Add 1 tbsp of chermoula marinade to a cup, dilute it with 4 tbsp of water and pour over the vegetables. Decorate the top with some fresh or preserved lemons, and olives for additional flavour.
Cook the tagine on low heat over a fire or on the stove until the fish is cooked through and the vegetables are tender.
When the fish tagine is ready sprinkle over with some fresh-cut parsley and serve it hot with some Moroccan bread for a truly authentic experience.