Heat the butter and olive oil in a large frypan over medium heat. Place salmon in the frypan and season with garlic, lemon pepper and salt. Pour 1/4 cup (65ml) water around salmon. Place tomatoes and coriander in the frypan. Cover and cook 15 minutes or until fish is easily flaked with a fork.
Bring 2 cups (500ml) water to boil in a pot. Remove from heat and mix in couscous. Cover and let sit 5 minutes. Serve the cooked salmon over couscous and drizzle with sauce from frypan.