Common Garden Fluke in Ponds

by Jenna Marie

Natural bodies of water contain countless varieties of fluke, a type of parasitic flatworm. The fluke thrives in stagnant waters and uses animals as hosts, especially pond fish, notes Parasitology.com. Pond owners should worry about flukes appearing in their backyard ponds or koi pond, as they can cause enough damage to kill off the fish and irritate other animals in the vicinity. While the most common North American flukes cannot use humans as a host, they can upset the balance of a pond's ecosystem. The most common flukes in North America are microscopic, and prefer bodies of water with muddy, sedimented bottoms, according to Austinparks.com.

Flukes thrive in ponds because the water is more stagnant.

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Skin Flukes

The skin fluke has a V-shaped head and hooks on one end of its body. The worm-like skin fluke, also called gyrodactylus, uses these small hooks to attach to a host. According to Koifish.com.uk, skin flukes often attach to the skin of koi, but they can also attach to other animals, such as dogs or birds. Affected fish may develop white or cloudy scales and will rub against pond features to ease the irritation caused by the skin flukes. If a pond owner suspects that skin flukes are present in the pond, there are chemical treatments (such as organophosphates) available that will kill off the flukes without harming the koi.

Gill Flukes

The rounded head, egg-laying capabilities and preference for the gill area on fish identify the gill fluke in a koi pond. Also known as dactylogyrus, the gill fluke is also equipped with hooks that irritate the tender tissues on animals. This fluke, as the name suggests, severely affects fish gills enough so that secondary infections can develop and eventually kill the fish, according to Koiandponds.com. One sure sign that a koi fish is infested with gill fluke is redness as well as a thick mucus layer around the gills. A gill fluke infestation can be treated using chemicals such as malachite green and formalin, but this parasite is more difficult to get rid of than the skin fluke.
Blood Flukes

A part of the schisosoma species, blood flukes are a prevalent type of freshwater fluke that can make an appearance in ponds. Blood flukes develop as either male and female, unlike other, unisex flukes. Blood flukes can infect humans who are exposed, and usually are transmitted into ponds via freshwater snails, which are intermediate hosts for the parasite. Blood flukes move from snails to fish or water birds. The blood fluke is not as common in North America; however, there are a few varieties present, according to Parasitology.com. Unlike the blood flukes of Africa and Asia,which pose a threat to human health, North American blood flukes cannot use humans as hosts.

Skin Flukes