You can substitute the broccoli for other vegetables such as Brussels sprouts, green beans or asparagus with little to no change to the amount of carbs in the dish.
If you want to use another kind of fish we primarily recommend other fatty fishes such as trout or mackerel but you can also go with white fish if you prefer.
If you don’t like cheddar you can use a mix of different cheeses. Half mozzarella and half parmesan will be just as good!