Gill Fluke (Dactylogyrus)
The gill fluke is a bit smaller than its big brother (the skin worm). The way of reproduction is also different. Young worms are born from an egg that has ended up somewhere in the pond. That’s why they have eyes, so they can look for a host. Once landed on a Koi, the small worm continues its way towards the gills, the softest and most delicate part accessible from the outside of the fish. The eggs that he lays afterwards fall off the Koi and the cycle can repeat itself after the egg has hatched. How long it takes for the eggs to hatch depends on the water temperature.
With a magnification of 40x, these worms can be found. However, to be sure, check if you can see the eyespots, which is best done at a magnification of 100x.
The gill fluke is a worm-like and falls under the category of Trematodes (parasitic flatworms).
Gill flukes are hermaphroditic and engage in self-fertilization.
Danger
The danger of the gill fluke lies in the following things.
It looks a lot like the skin worm. It is important that you know which parasite you are dealing with.
With a gill worm you have to treat several times because the pesticide does not fight the eggs.
Treatment is done by means of an anti-worm medicine. These products are widely used in livestock farming and veterinary practices (deworming dogs, cats, pigs, chickens) and resistance is increasing. Hobbyists are inclined to use a remedy that works well next time, while it is wiser to switch products next time.
Some active substances against worms are: praziquantel, flubendazole, triclabendazole.
Only use such a pesticide if the situation really requires it. A single gill fluke can solve a healthy Koi just fine.
Name: Gill Fluke (Dactylogyrus)
Species: Wedge-like, Trematode
Multiplication: Oviparous
Size: 0.3 mm (=300 micron)
Magnification microscope: 40x-100x
Recognizing: Head side is divided into quarters, eye spots, two hooks in a whorl of small hooks
Cause of outbreak: Poor water quality, stress, contamination
Symptoms: Abnormal behavior such as head shaking, air gasping, fin pinching, jumping, keeping one gill cover closed, excessive mucus production in the gills, chafing, not eating, seclusion, listlessness.
