Combine the ras-el-hanout ingredients and grind into a fine powder.
Heat a tagine or heavy casserole over medium-high heat.
Heat oil in the tagine and fry the garlic until golden-brown.
Add the onions and cook slowly for 10-12 minutes until softened.
Push onions aside and fry cumin, ras-el-hanout, and cayenne pepper until fragrant.
Stir in tomatoes and simmer for 2 minutes with seasoning.
Add 110ml of fish stock and bring to a simmer.
Place fish fillets in the sauce, cover, and cook for 8 minutes on low heat.
Mix couscous, oil, and lemon juice in a bowl with 250ml boiling water.
Cover and sit for 5 minutes, then fluff the couscous with a fork.
Stir pistachios, pomegranate, and coriander into the couscous and season.
Finish the tagine with lemon juice and coriander leaves before serving over the couscous.