Aside from stinking up the microwave, fish should never be reheated in a microwave. Most fish is just as delicious cold as it is when it was warm. Leftover fish can be repurposed to make salads, fish cakes, or tossed in soups. If warm fish is the only fish that will do, then take out the grease up the skillet and reheat the fish on the stove top. The main thing against reheating fish is the lasting, ever lingering fishy smell. Of course, reheated in a microwave also affects the taste, texture, and protein composition as well.
The main staple of many dishes, rice is one of the foods that is both shocking and disappointing to know that it cannot and should not be reheated in the microwave. Before rice is cooked, the spores of the bacteria Bacillus cereus, which is known to cause food poisoning are present. Once the rice is cooked the heat destroys the bacteria, but once left to cool to room temperature, the spores will respawn and are naturally very heat resistant. Food poisoning can be life-threatening and even deadly due to dehydration and loss of fluids.