Is it safe to eat food that was heated in plastic wrap to the point the plastic wrap flamed?
There are multiple types of film wrap, which are different plastics.  No matter what yours was made from, it almost certainly partially burned up, partially melted, and partially had other heat-based reactions leaving unknown remains on your food, possibly including dioxins, which are quite toxic.

In any of these cases, I would not risk finding out.

Discard the fish.