Puneet Varma (Editor)


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Kingdom  Animalia
Family  Dactylogyridae
Phylum  Platyhelminthes
Order  Monopisthocotylea
Class  Monogenea
Scientific name  Dactylogyrus
Rank  Genus

Similar  Gyrodactylus, Monogenea, Trichodina, Ichthyobodo necator, Argulidae

Dactylogyrus gill fluke

Dactylogyrus is a genus of the Dactylogyridae family. They are commonly known as gill flukes


Like other monogeneans, Dactylogyrus only has one host required to complete its life cycle.

Gill fluke dactylogyrus diagnosis and treatment on koi


Adult dactylogyrus showing its 4 eye spots

Dactylogyrus (common name: Gill Fluke) are oviparous monogeneans that have two pairs of anchors. These anchors can be used to latch onto the gills of a host, particularly freshwater fish such as carp. In heavily infected fish, Dactylogyrus can also be found on the buccal cavity. Other characteristics of the Dactylogyrus include the appearance of four eye-spots, 14 marginal hooks, one to two connective bars and two needle-like structures and spindle-shaped dactylogyrid-type seminal vesicles. Dactylogyrus has an adult structure that is up to 2 mm long.

Life cycle

Dactylogyrus extensus

The Dactylogyrus life cycle is direct, having no intermediate host. The hermaphroditic adults are oviparous and produce eggs into the water which hatch prior to attaching to the gills of a fish host and developing into an onchomiricidium.

Parts of Dactylogyrus

After the eggs hatch, water currents aid the free-swimming ciliated larva in reaching its host. The time required for egg maturation into the adult form is temperature dependent. Water temperatures of 72–75°F allow life cycle completion in a few days, whereas temperatures of 34–36°F extend the generation time to five or six months.



Dactylogyrus is a monogean parasite that is usually found on the gills of Cyprinidae fishes. The prevalence of Dactylogyrus infection on fish differ depending on the seasons. It was found that Dactylogyrus infections are at their greatest during late autumn or early winter. Correlation has also been found between the temperature of the water and the intensity of Dactylogyrus infection.

It is also generally accepted that fish are exposed to increased Dactylogyrus infections during their spawning period.


Dactylogyrus on gill filaments

Cyprinidae that are infected by Dactylogyrus may have symptoms that include inflamed gills, excessive mucous secretions and accelerated respiration. The infected fish also becomes lethargic, swims near the surface, and its appetite decreases. Additionally the infected fish may hold its gill covers open and scratch its gills on rocks.

Gill of common carp parasitized by Dactylogyrus

In severe infections, Dactylogyrus can cause hemorrhaging and metaplasia of the gills which can lead to secondary bacterial infections and death. Heavily infected fish are also anorexic and can be found gasping for air and exhibiting abnormal behavior such as jumping out of the water.


Dactylogyrus Gill Fluke

A primary method for control of Dactylogyrus is the application of chemicals. Treatments include Praziquantel, salt baths, formalin or organophosphates, fenbendazole,albendazole,Bromex-50 and potassium permanganate.

The ventral view of a Dactylogyrus lamellatus


Dactylogyrus Wikipedia