How to make white sauce "for fish tacos?

I need a recipe for a good sauce for fish tacos. Other fish tacos I've had a very good white sauce on them …. What is this sauce made? Thank you.

Try this: You http://allrecipes.com/recipe/grilled-fish-tacos-with-chipotle-lime-dressing/detail.aspx can find other recipes, write "recipe for fish tacos" on Google.