cooking fish to keep?

i bought some fish for dinner and it proved to be too much. since my fridge has broken down, i am thinking of cooking it in the microwave and keeping it so that i can cook it again tomorrow. any tips or suggestions?
i have slices of King fish

After cooking fish, does microwaving it deplete it of its nutrients or more specifically omega 3 fatty acids?

After cooking the fish on a grill outside, then storing in the fridge, then microwaving the fish deplete it of its nutrients and more specifically omega 3 fatty acids? Is it better to eat vegatables raw or cooked?