The most common fish parasites seen by the unaided eye are yellow grubs and black grubs. Grubs appear as tiny specks on the fins, skin or flesh of fish. These parasites go through a life cycle that inhabit fish eating birds such as herons or kingfishers, snails and then fish. Control is obtained by eliminating one of the hosts; this often is difficult and perhaps even undesirable. Stocking Redear sunfish will eliminate the snail population and break the life cycle of the grub. Reducing the amount of aquatic vegetation with grass carp can also reduce the number of snails and the level of grub infestation. These parasites will not develop in humans, and all parasites are killed by cooking or freezing. Most people think it best to fillet out the infected flesh and cook the rest as usual. However, incidental ingestion of cooked fish parasites is not harmful.
Other parasites can be a problem to fish health; one of the best solutions is to buy fish from a reputable dealer that has treated the fish for parasites. They should be guaranteed to survive for at least 10 days. For more information about fish parasites, consult Additional Information.