Heat the olive oil in a large skillet. Add onions and peppers and saute for about a minute. Cover and cook until onions are tender, about 5 minutes. Add the carrots, tomatoes and their juices, cumin, saffron and crushed pepper. Cover and cook until carrots are tender, about 5 minutes
Add chick peas and monkfish. Cover and simmer until fish is cooked through, about 10 minutes While fish is cooking, bring fish stock to a boil. Add couscous and immediately remove from heat. Let couscous steep about 5 minutes. Remove from heat and add butter; season to taste with salt and pepper. Ladle couscous in a bowl and ladle soupy monkfish stew over the top.