In a medium saucepan, bring 3 cups (750ml) water to a boil, and stir in the couscous. Remove from heat, cover and let sit 5 minutes.
Heat the olive oil in a frypan over medium heat, and saute the onion and green capsicum about 5 minutes, until tender. Mix in the garlic and continue to cook and stir about 2 minutes. Mix in the artichoke hearts with reserved liquid, capers with reserved liquid and olives. Stir in the tomatoes, wine, lemon juice and 1 cup (250ml) water (or enough to attain desired thickness). Season with sumac powder, chilli flakes, basil, cumin, ginger and pepper.
Bring the mixture to a boil and mix in the fish chunks. Reduce heat and simmer 10 minutes, or until the fish is easily flaked with a fork. Serve over couscous.