Chop the onion.
Pour olive oil into a large casserole over a medium heat. Once casserole is hot, add the chopped onions.
Simmer the onions a few minutes until they are translucent.
Add minced garlic and continue to simmer another minute.
Add the dried spices and herbs. Continue to simmer a minute or two. (Fresh herbs and spices should be added at the last minute.)
Add the white wine and stir. Simmer a few minutes. The white wine should clean the bottom of the casserole
Add the tomatoes and continue to simmer with the casserole uncovered until the tomatoes break down into a sauce.
Add the water and bring it to a boil. Turn down the heat slightly.
Add the cut fish and shellfish. Continue to simmer until the fish becomes opaque and shellfish are cooked (shrimp should be opaque; the mussels and clams should have their shells open).
If you are using fresh coriander, add it in the bowls as you serve it. Enjoy it!