Raw fish does come with a higher risk than when fish is cooked. However, if raw fish is fresh, stored correctly and prepared correctly, then it is safe to eat. Certain types of fish are recommended for eating raw. This includes fish that lives in cooler water, certain types of farmed fish and fish that is frozen to below -4 degrees C soon after catching. The cooler waters and freezing of the fish kills any bacteria and parasites, so making it a lot safer to consume raw. However, people at higher risk of food borne illnesses should always avoid any kind of consumption of raw fish. Higher risk people include those with low immune systems, pregnant women, infants, young children and older adults. Always check with your GP if you are in any way unsure and have a read of this NHS page about sushi for further info.