Canh Mồng Tơi Nấu Riêu

1 lb ceylon spinach, thinly sliced
10 oz frozen Oceanic crab
3 T fish sauce
pepper to taste

Add 4- cups of water in a medium pot, bring to boil on high heat. Add crab and turn to medium heat, cook for 10 mins. Add Spinach, fish sauce, pepper to taste. Bring back to boil, serve.