Gyrodactylosis is a disease that is caused by flatworms belonging to the genus Gyrodactylus. Aquarium fish affects several species of this parasite, but, as a rule, the most common parasite is Gyrodactylus elegans.
It looks like a transparent, flat worm up to 1 millimeter long.
The causative agents of gyrodactylosis are very similar in appearance to the causative agents of dactylogyrosis, only the front part of them is two-lobed, and not four-lobed. The eyes are missing, on the attachment disk, at the rear end there are a pair of large hooks and 16 edge hooks.
The internal organs of the parasite are well visible, the branchy intestine, which originates from the pharynx and ends in the back, is especially well marked. In the middle part there is a testis and a V-shaped ovary.
Gyrodactylus are viviparous parasites, most of the internal cavity is allocated under the embryo with two hooks. If you look at the worm under a strong magnification of a microscope, then you will be able to see how a new smaller germ is already ripening inside a single embryo, and also with a pair of hooks.
For a long time, specialists could not understand how causative agents of gyrodactylosis develop with such an infinite number of embryos in each other. Uncover the veil of secrecy could only relatively recently.
It turned out that the fertilized eggs of gyrodactylus remain inside the parasites and are divided in half. One half gives the embryo, which is absorbed by the remaining half of the egg, and it will also be divided in half.
The resulting part will give rise to the next embryo, which also embraces the rest of the egg and again turns into an embryo. It turns out that one maternal organism is able to give birth to three gyrodactylus, like a matryoshka.
The germ that is released by the parasite is a well-developed larva that tends to firmly attach itself to the victim, otherwise, it is inevitable death. Despite the fact that the parasites can live for up to 7 days without a carrier, the larvae cannot safely swim in the aquarium, as it may lose its owner and will eventually die.
This applies to sparsely populated aquariums. Unlike the parasites of dactyloguiruses, gyrodactylus settle on surface areas of the body or fins of fish, on the gills much less often.
A sick fish becomes restless, tries to rub against the ground or other aquarium decorations, hangs for a long time in one place, or makes oscillatory movements around the sides. With an increase in mucus secretion on the skin of a fish, a grayish-blue dull plaque forms. Because of the damage by hooks on the skin, small ulcers form in the fish, and if the parasite has chosen fins, they contribute to the destruction of the interlord tissue.
A little later, the sick fish stops eating and reacts poorly to stimuli. Damaged areas of the body are exposed to saprolegnic fungi, causing the development of another disease – saprolegniosis.
If the fish does not receive timely treatment, it will die.
To confirm the diagnosis under microscopic it is necessary to take scrapings from the body of the fish, gills and fins of the infected fish. If parasites are found on the body of fish, pets should be fished out of the aquarium and treated in a separate container using the following method:
- On the first day, fish are treated with a solution of table salt based on the proportion of 100 g of salt per 10 liters of water at a 30-minute exposure; then the fish are transplanted into a container with clean water and on the second day they are fed by a pipe maker or a live bloodworm;
- On the third day, the fish are treated with a formalin solution based on the proportion of 2.5 ml per 10 liters of water at a 30-minute exposure; then the fish are transplanted into clear water and on the 4th day you need to feed them with live food;
- On the fifth day, a solution of violet basic is introduced into the tank with the fish on the basis of a protation of 0.002 grams of substance per 10 liters of water with 4-day exposure. In the aquarium should be a powerful aeration and abundant feeding with live food; After all these procedures fish can be returned to the general aquarium.
In the process of treating fish in a separate container, the water temperature in the general aquarium should be maintained within 27 – 30 degrees in order to facilitate the accelerated extermination of parasites. Prevention of causative agents of gyrodactylosis is in no way to prevent from falling into the common aquarium.
Among other things, in reeds and common aquariums should not be a dense landing of fish.