Marinades are commonly used with seafood because they enrich the flesh helping to retain its moisture during cooking – over the intense heat of a charcoal fire, frying or baking. At the same time marinades add lots of flavour.
Marinade recipes can include so many different ingredients – coconut milk, citrus juices, herbs, wine, curry powder, even crushed raspberries. The addition of oil or melted butter helps conserve the moisture and succulence of the fish as it cooks.
In general, any marinade should include an acid ingredient (wine, citrus juice, yogurt, vinegar, spirits), a fatty ingredient (oil, butter, coconut milk) and flavourings (spices, herbs, fruit, garlic, mustard).
You could play around with favourite ingredients and create your own unique marinades.