How to get rid of parasites in fish tank

To know how to get rid of parasites in fish tank first you need to understand what kind of parasite it is. Most of the fish contained in aquariums come from foreign, mostly tropical, countries that our compatriots usually call exotic. If you follow this principle, then the parasites of these fish can also be attributed to exotic.

How to get rid of parasites in fish tank?

It is believed that a small number of parasites cannot harm the animals of the aquarium, as they have enough food in the water. But if these worms are found in large numbers, they must be combated. There are several effective techniques for destroying parasites in a fish tank:

  • Trap. It is not difficult to make it out of a small gauze bag and a few fresh pieces of meat. The trap is fixed at night, during which time the parasites are stuffed into it and they can be thrown out. This method is safe for other residents, but you can not solve the problem immediately.
  • Complete disinfection of the aquarium itself, floor, driftwood, filters, various interior equipment. To destroy the worms and their eggs, everything must be treated with bleach, washed, and well dried. New water is poured into the aquarium.
  • Increase the water temperature in the aquarium to 35 degrees and higher for about two hours. At this time the fish are naturally deposited. From the effects of high-temperature die and the turbellarians.
  • Worms in the aquarium are destroyed by the fish itself. Eat parasites of both species paradise fish, firemouth cichlid, apple snail.
  • In an animal pharmacy and more rarely in pet shops, you can buy a special remedy for worms in the aquarium that contains Fenbendazole. Use these medications according to the instructions.

To get rid of parasites in fish tank can be preventive measures. This is the purchase of plants only in big stores and their preliminary quarantine before landing in the aquarium. All equipment in the aquarium must be processed, change the water as needed, and do not overfeed the fish.

Types of parasites

Indeed, there are always differences between parasites on our (i.e. local) and “foreign” fish. They include not only morpho-systematic-based on structure but also other biological differences, which are primarily manifested at the level of host-parasite relationships.

For example, experienced fishkeepers are already well aware that there is not only a “domestic”, common but also a “tropical” ichthyophthirius arriving on fish from abroad.

In addition to the differences in the structure of these infusoria visible only under the microscope, the exotic species is more dangerous than usual, since it can reproduce not only in water but also directly on fish, under the protection of the host’s epithelial cells, forming a kind of “nest”.

Its a lot harder to get rid of parasites in fish tank in the “tropical” ichthyophthirius also consists of its increased thermophilicity. As a result, at relatively low water temperature, it develops very slowly, as if it is hidden, while the temperature increase to 32-34°is disastrous for the ordinary ichthyophthirius only accelerates its development.

The differences between the common Ichthyophthirius multifiliis and the “tropical” Ichthyophthirius were so significant that the latter was described by O. Bauer and O. Yunchis in 2001 not only as a new species but even separated into a new genus – Neoichthyophthirius schlotfeldti.

How To: Detect and Treat Internal Parasites

The parasite on the fish Tetrahymena

To other dangerous exotic ciliates include epistemic and Tetrahymena. The first is classified as a systematic group of sessile infusoria.

The lower, stalk-like end is firmly attached to the skin of the fish, while the upper one has a mouth opening surrounded by cilia. The latter drives food consisting mainly of bacteria and small organisms into the mouth of the infusoria.

Because of this method of feeding, these infusoria can not even be attributed to real parasites and, it would seem, the damage caused by them should be small.

Indeed, epistylis from our freshwater fish form small colonies and are almost harmless. However, according to American scientists, some tropical species of these infusoria can cause the death of even large “hosts”.

With mass reproduction, tropical epistylis form numerous and dense colonies on the body of fish-settlements that look like a piece of white wool or cotton wool. Infected individuals, primarily cichlids, are restless, itchy, and try to get rid of harmful “settlers”. Over time, an inflammatory and necrotic skin lesion develops around the growth zones of infusoria.

Parasite hymena corlissi

Externally, the symptoms of fish infection with epistylis are very similar to the defeat of Neoichthyophthirius schlotfeldti. Accordingly, before starting treatment, it is necessary to accurately determine the pathogen. Given the high resistance of epistylis to various medicinal preparations, the effective way on  how to get rid of this parasite in fish tank such “neoplasms” is by scraping and then treating the wound with furacillin powder (furazolidone) or antibacterial ointment.

Tetrahymena, extremely dangerous ciliate of fish, nicknamed “killer guppies”. It infects other exotic inhabitants of aquariums, but the mass death from this parasite is noted primarily among Poecilia reticulata(Guppy).

As in the case of Ichthyophthirius, we are dealing with at least two species. The species that live in our waters are usually not very dangerous and, as a rule, is found already on dead fish, being a kind of nurse.

The exotic (or” tropical”) species Tetrahymena corlissi causes an outbreak in individual batches of aquarium fish, usually a few days after they arrive from abroad. Infusoria of this species are able to feed on the host tissue, penetrate under the skin, into the muscles, and even into the internal organs, where they multiply in huge quantities.

The question of the extremely high aggressiveness of exotic tetrachimens has not yet been fully resolved, because under normal conditions they behave like free-living infusoria and do not attack fish. There are two versions explaining the unusual aggressiveness of exotic Tetrahymena in relation to viviparous tooth carps. The first and most likely – poor fish tolerance of long and extreme transport conditions, which leads to a sharp decrease in protective forces, immunity. The snail is not able to withstand the massive reproduction of Tetrahymena. Infusoria first eat bacteria on the body of fish and then go on to feed on the host cells, penetrating deep into the tissues.

The second version is the acquisition by some individuals of tetrachimens at the genetic level of increased aggressiveness and the formation of forms that are pathogenic to fish, which is also often observed in bacteria that live in water.

Parasite monogenea

In any case, losses from Tetrahymena among imported guppies and other inhabitants of tropical rivers can be very high, and treatment is often ineffective.

Survivors of the outbreak of guppies do not suffer from tetrahymena in the future and are usually no longer dangerous as a source of infection for other fish in home aquariums.

A large and extremely dangerous group of ectoparasites is represented by monogeneans belonging to the flatworm type in the class rank. Among freshwater fish, the most numerous are monogenean viviparous (order Gyrodactylidea) and oviparous (order Dactylogyridea). While members of the first order can live both on the skin and on the gills, representatives of the second-order usually parasitize only on the gills, for which they were previously called Gill flukes.

The main morphological feature of monogenea is the characteristic structure of the attachment apparatus, usually armed with hooks.

A second distinctive feature is a large number of species with their high specificity. Each species or group of closely related fish has its own “set” of monogenean, which differ in structure, biology, and sensitivity to medicinal drugs.

For example, only for carp, which are one of the most well-studied parasitologically fish species, at least 6 species of monogenea of the genus Dactylogyrus and 4 species of the genus Gyrodactylus are known.
Accordingly, almost every species of exotic fish is parasitized by its own specific monogenean species that do not infect other fish.

Parasites on the gills of fish

Most fishkeepers, apparently, have already had the sad experience of “personal meetings” with these extremely dangerous ectoparasites of fish, or have read about them. Given the huge amount of information available, monogeneans obviously need to devote a special publication.
At the same time, I consider it necessary to introduce readers to relatively rare ectoparasites of fish – really exotic.

In addition to the monogenea class, the flatworm type also includes the trematode class. If monogenea are primarily parasites of fish, the flukes are able to “infiltrate” all the groups of vertebrate animals, including birds and mammals.

Unlike monogenea, flukes are endoparasites, i.e. they live in the host’s body – in its organs and tissues, including blood. But, as you know, any rule can have exceptions. I want to focus on two examples from my personal practice in more detail because in them gill flukes act in an unusual role of ectoparasites.

In many fish of different species arriving from abroad, clearly foreign “inclusions” can be detected by microscopy of the Gill tissue. Their number in a single individual can vary from units to hundreds. It turned out that these are incised metacercariae (i.e. larval stages) of trematodes, whose final hosts are fish-eating birds.

The most common species is Centrocestus formosanus, found in China, Japan, Thailand, and many other Southeast Asian countries.

A distinctive feature of metacercariae of this species is the presence of a collar of spikes around the oral sucker.

The formation of cysts, and then capsules around the parasite leads to the destruction of the gill tissue of fish. In the case of mass infection, sick individuals are more sensitive to the lack of oxygen in the water than healthy ones. The process of aging and death of metacercariae in cysts is often accompanied by an inflammatory reaction from the host body and, as a result, concomitant complications, infection.

Given the complex life cycle of flukes, you can not be afraid of the reproduction of this parasite in aquariums. At the same time, the presence of metacercariae indicates that the fish infected with them are grown in ponds in the open air (that is, where birds had access), on natural food, and, accordingly, they can have a variety of parasites.

When I study fish diseases, I am always wondering how to get rid of parasites in the fish tank. For example, free-living microscopic rotifers-the usual food of fish larvae in natural reservoirs-suddenly find themselves scraped off the surface of the body of a sick aquarium fish.

Similarly, on the body or gills of my “patients”, you can find small filamentous nematodes that usually live in the ground of the aquarium, as well as harmless flagellates or infusoria.

Many years of experience allow me to distinguish quite easily between free-living organisms and similar parasitic species. The mild surprise that arises from such findings is quickly replaced by a sense of satisfaction with the correct definition of harmless organisms that are out of place. But recently there was an incident that seriously puzzled me.

In a batch of black common molly Poecilia sphenops that came from abroad, some fish had whitish scales on their backs. There was an impression that a lot of mucus had accumulated under them, which partially protruded out. However, when scraping, it turned out that the scales hide white sedentary worms of a completely unusual shape. The width of their bodies clearly exceeded the length, which is quite unusual for helminths.

The internal structure of the body was also mysterious. The well-visible large pharynx and other details of the anatomy made it equally possible to classify them as monogeneans and flukes. The location under the scales indicated an ectoparasitic lifestyle, which is typical for monogenea, not for flukes. At the same time, according to all literature data, such monogenea have not been found before.

Parasites on common molly

In this impasse, I had to seek advice from helminthologists. which identified the strangers as trematodes from the unique family Transversotrematidae. Printed works on these parasites are very few and old, but they still managed to find out that different species of two genera of these trematodes were found in the fish of Australia, Ceylon(now Sri Lanka), and the Philippines.

In the course of experiments conducted by foreign researchers, it turned out that parasites in fish easily infected mosquitofish, Xiphophorus, Poecilia, paradise fish, Mozambique tilapia and other fish species. Thus, we were able to find a very rare and really exotic parasite that was imported. Perhaps someone has already observed a similar “miracle” on their fish, but could not determine its systematic position.

In conclusion, I would like to note that although the parasites of exotic fish have become more actively studied in recent years, but given their diversity, we still have many unexpected finds ahead of us.

In practical terms, an extremely important, but poorly studied area remains the different susceptibility to medicinal products of both the tropical inhabitants of the aquarium and their parasites.