There are many parasitic crustaceans throughout the fish kingdom, the one most commonly seen in pet fish is Argulus ssp., also known as “Fish Lice.” Under the microscope, they are one of the strangest looking parasites you will come across.
These parasites are found in salt and freshwater all around the world. We do see them in many pet species of fish. Fish lice have stylet that punctures the host fish to feed on body fluids (yum!). This causes extensive skin irritation and severe infestations can infect the gills and kill fish. Due to the penetration, secondary bacteria and fungi can also infect your fish.
Treatment of fish lice requires some serious drugs, some of which are not available in certain states. Prior to starting treatment, make sure your water quality is within range and there are no secondary infections to worry about. Many over the counter medications are only effective at treating juvenile stages, not adults. Our office has seen many severe infestations that take hours to remove all of the lice present.