Fish pie recipe calls for light cream (in pie, not crust). Can I substitute something for it that is less calorie-laden?

I usually top my fish pie with mashed potatoes much like Shepard pie.

Having said that I would not worry about the minimal amount is cream in the pie filling but whole milk should work but not be as rich.

Sorry misread this re the crust. What type of pie is it?

well a pie crust is rather calorie laden already, so I don't think you'd be saving much by subbing something for the cream. If the recipe only calls for a tablespoon or two, though, you'd probably be fine subbing whole milk.