It happens that aquariums are invaded and populated by “pest” organisms that cause fears to aquarists, although they are harmless by nature. Sometimes these concerns are not unreasonable, since the presence of large numbers of these organisms in the aquarium (which is an epidemic) is a sign of a deterioration of the fish’s habitat. In addition, this indicates a lack of attention to detail on the part of the aquarist: he does not check the live food in which they may be present, and collects decorative material in natural water bodies populated by fish, which should not be done.
Such pests are unpleasant in appearance and create certain inconveniences. Although they do not directly harm fish, their presence is a warning signal and should not be ignored.
Water donkey Asellus
Asellus donkeys are aquatic crustaceans, also called aquatic lice. They have some similarities with woodlice, whose relatives they are.
They can be brought into the aquarium with live food (or as a live food), and they inhabit the inaccessible gaps in decorative objects, as well as a filter. They do not bring direct harm to fish, but can play the role of intermediate hosts for acanthocephalus (prickly headed worms).
These worms rarely infect aquarium fish, so there is no need to worry about it. However, a large population of water donkeys Asellus indicates that in the aquarium there is a strong organic pollution, to which these creatures make an additional contribution.
These are annelid worms from the family Naididae, reaching a length of 2 cm. They are characterized by the presence of bristles (it is probably thanks to these bristles that they are inedible for fish).
Most often it is white or pink worms that breed by budding or egg deposition. They can be brought into the aquarium together with plants, in the shells of aquatic snails or with water, in which they carried live food caught in the wild. In an aquarium, they can live in a layer of soil or on its surface, feeding on detritus.
Therefore, their presence in a significant amount is an indicator of poor hygiene of the aquarium and the danger to which fish are exposed due to contamination. By themselves, these worms are harmless.
Improving the hygiene of the aquarium will make it possible to control their number and benefit the fish, as it will improve their living conditions.
Algae are lower aquatic plants, which, depending on the species, either attach to underwater surfaces or live freely in water. They may have a different shape and color (green, brown, red, gray, yellowish).
In appearance, they may resemble a mucous coating or fluffy tufts, form a carpet resembling moss, or long fibrous tufts (for example, tina, which we see in the summer in ponds). Real algae differ from the so-called blue-green algae, which are scientifically classified as cyanobacteria.
The presence of algae is inevitable where water, nutrients and light are present at the same time. All three elements are in every aquarium, so an aquarist must learn to put up with the fact that algae are a natural and inevitable part of the aquarium ecosystem. In the aquarium, as in nature, algae provide a number of advantages.
They are a natural food for some herbivorous fish. Together with the microorganisms living on them, they are an excellent source of the first food for fry.
They reduce the amount of nitrates in water that are used as food. In addition, algae give completely bare decorative objects – such as stones – a more natural look, because in natural waters, stones are usually covered with algae.
If the algae grows too rapidly, it is a warning about possible problems with water quality.
Different aquariums are populated by completely different types of algae. This is partly dependent on the lighting of the aquarium, and poor lighting favors the development of brown mucus algae, and bright lighting encourages the growth of bright green algae.
It is believed that algae cause particular inconvenience when they cover aquarium glass and plant leaves. However, it is not difficult to keep the front glass of the aquarium clean with a scraper or magnetic wiper.
Algae can be left on those glasses aquarium, which are not used for review. Staying there, the algae will help remove nitrates and provide food for the fish.
If the aquarist has a penchant for photography, then for him the back glass covered with algae is an added advantage because it prevents the flashlight from reflecting light.
In nature, a completely normal phenomenon when algae cover the old leaves of aquatic plants. Such leaves die off and are successively replaced by new leaves. If algae on aquarium plants create problems, it is usually too fast algae growth or not enough intensive growth of higher plants.
Aquarists often make a mistake by reducing the intensity or duration of lighting in an aquarium and trying to contain the growth of algae. But instead, they restrain the growth of higher plants and thus further exacerbate the problem!
Healthy plants help restrain algae growth by competing with them because of the available nutrients.
If it is necessary to remove the algae from the sight glasses every few days, this means that the algae grows too rapidly. This phenomenon occurs when there is an excess of nutrients.
Algae are becoming a real problem – a sign of high levels of nitrates or phosphates. This, in turn, may be due to a too high dose of aquarium fertilizers designed to accelerate plant growth, but more often is an indicator of poor care for the aquarium — its overcrowding, overfeeding of fish, insufficient volumes of substitute water, excessive waste or a combination of these factors. In tap water used for partial water changes in an aquarium, there may be too much nitrate and other substances that serve as food for algae.
Thus, not the algae themselves, but the reason for their excessive growth, whatever it may be, is what needs attention! Otherwise, the health of the fish will be adversely affected – due to contamination of the aquarium, and not because of the algae themselves!
Free-floating algae, which are invisible to the naked eye, sometimes multiply to such an extent that the water becomes turbid and resembles a pea soup. This is the so-called “bloom of water.”
Such a phenomenon can be observed in summer in the ponds, but it can be in the aquarium, if it is illuminated for a long time by bright sunshine. And this problem is also an indicator of high levels of organic pollution.
Although special aquarium products are available for the destruction of algae, solving this problem, which is too easy to see, is not really a solution. The death and decomposition of large amounts of algae can lead to an overload of the filtration system and further exacerbate the problem of pollution, which has caused rapid algae reproduction.
Even if this does not happen, dead algae will further increase the organic matter content in the aquarium. Therefore, when the algae populate the aquarium again (and this will inevitably happen), then the problem will become even more acute than the first time.
Repeated use of chemicals for algae control and biological overload will almost certainly have adverse effects on fish and higher vegetation. Therefore, it is better to establish and eliminate the cause of excessive amounts of algae, and if their growth is of a normal nature, consider them as friends rather than enemies.
Some fish — for example, the gyrinohailus Gyrinocheilus aymonieri and some catfish with a mouth sucker — are known algae-eaters, so they can be used to contain algae growth. However, this method does not negate the need to maintain a low concentration of organic waste in the aquarium.
Copepods are small aquatic crustaceans. Most of them are harmless to fish.
Some free-living species — for example, Cyclops (Cyclops) —are used as live food. At the same time, representatives of some species of copepods parasitize on fish.
Free-living harmless copepods are, as a rule, translucent and reach a length of 3 mm. They move in short jumps, but can also lie on underwater surfaces, including on aquarium glass, where they are either placed intentionally (as a live food) or accidentally (on plants). Few manage to survive in the aquarium for a long time – for most fish it is a real delicacy.
True, large fish do not pay attention to them – because they are too small and should not be eaten. Thus, the infection of an aquarium free-living copepods can occur only if the fish do not eat them – either because they are unsuitable food, or because the fish feel so bad that they have lost interest even in such a seductive food source. . This may be due to environmental pollution (heavy organic load).
If copepods begin to breed in an aquarium, then organic contamination takes place there.
If you eliminate the problem that caused this behavior of the fish, the fish with great pleasure will solve it themselves.
This is a group of microorganisms that causes the growth of a substance resembling algae. Aquarists call it “blue-green algae.”
The appearance of such “algae” is associated with a high level of nitrates and phosphates. However, not all aquariums with a large amount of organic waste are filled with these “algae”.
They can cover all the decorative objects in the aquarium, including the ground, with a slimy bluish-green patina overnight. There is no evidence that they cause direct harm to adult fish (but they can be damaged by poor water quality, which has caused rapid reproduction of cyanobacteria). However, the fry lying on the ground or decorative objects, these “algae” can very quickly cover and strangle.
In addition, they can completely cover the plants and destroy them.
It is very difficult to completely get rid of blue-green algae. Subsequently, with the slightest deterioration of water quality, they can again begin to multiply rapidly. The only way out is to reduce the amount of organic waste and each time during the next partial water change to filter out as much of this green mass as possible.
Unfortunately, the blue-green algae, the fish seem completely tasteless. It is said that groundwater snails feed on sandy sandwiches feed on these algae, but none of the authors of this article can confirm this from their own experience.
In addition, these snails create no less inconvenience than the cyanobacteria themselves.
These small intestinal cavities are freshwater relatives of the sea anemone. In length, they can range from 2mm to 2cm (including tentacles).
They are shaped like a stalk capped at one end by tentacles, while the other end attaches to a solid base. All these signs allow you to unmistakably recognize them. However, sometimes they are compressed into tiny jelly balls.
Their color can vary from cream to gray or light brown. (There are hydras of a pleasant green color, which can be easily mistaken for algae. – Approx. Consultant.).
Hydra (Hydra) sometimes enter the aquarium with live food or decorative objects collected in nature. Subsequently, they are arranged on some objects or aquarium glasses and represent additional interesting objects that are almost as charming as the main inhabitants of the aquarium.
For adult fish, hydras are safe, but they can catch fry and other small fish, as well as small pieces of food intended for fish. Sometimes their numbers reach such a level that they become real pests.
Like many other pests, they indicate problems with caring for an aquarium.
To completely destroy the hydra, it is necessary to completely empty the aquarium, scrape all its surfaces, wash gravel, decorative objects and scuba equipment in a hot 2-5% saline solution at temperatures above 40 ° C. If the aquarium is planted with plants, then these plants are unlikely to accept cleaning in hot salt water! Therefore, it is better to apply an alternative method, which is to remove all fish (as well as snails, if they are the desired inhabitants of the aquarium) from the aquarium to a temporary room and raise the temperature of the water in the aquarium to 42 ° C for half an hour. At the time of heating, the filler, which serves as a substrate for bacteria, should be removed from the internal filters, but the filters themselves should be left in place, because the hydra are attached to their surface.
External filters should be turned off, but no more than an hour, otherwise the population of bacteria may die due to the lack of oxygen. Then the aquarium should be allowed to cool to normal temperature or cool it by partial water changes, topping up with cold water.
After that, you can run the fish again (and also the snails) and restore the filtering.
In the fish-populated aquarium, the hydra population can be controlled by dissolving table salt in water — a solution of 0.5% saline should be obtained. This solution should be maintained for about a week, and then gradually get rid of salt by repeated partial water changes. This method can be used only if all fish tolerate such salinity well.
Otherwise, it will be necessary to regularly clean the glass of the aquarium, filter out the separated hydras, and remove stones and other hard decorative objects from the aquarium and process them in hot saline water.
Some species of fish feed on hydras (especially gourami, as well as young cichlids, “grazing” on stones). Therefore, they can be used to control the size of the hydra population, but only if these fish are suitable inhabitants for the aquarium in question.
Leeches are accidentally entered into an aquarium, and they can be seen on decorative objects or freely floating in water. Representatives of some species of leeches parasitize on fish.
This is a large group of filamentous worms, also called roundworms. Among them are both free-living and parasitic species.
Non-parasitic nematodes are red-brown worms with a non-segmented body 1-3 cm long. Sometimes they inhabit the substrate and biological filter. They can be brought into the aquarium with live food, and they are completely harmless.
If they become too numerous, this suggests that adjustments are needed in aquarium hygiene and fish feeding. These improvements are the only thing needed to reduce the number of nematodes.
The shellfish crustaceans of Ostracoda are bean-shaped crustaceans, reaching a length of 4 mm. Sometimes you can see them scurrying around on the substrate, like tiny moving specks. These creatures are yellowish or black-brown.
They attach their eggs to plants, so they can be accidentally brought into the aquarium with plants, as well as with live food. In aquariums, they are found in small numbers, but if the aquarium’s hygiene leaves much to be desired, they can begin to multiply rapidly and become a real disaster.
Thus, although crustaceans are harmless, their presence indicates that there are environmental problems or fish feeding. These problems may have adverse effects on fish.
Improving aquarium care is a simultaneous solution to both problems. It allows you to control the number of these animals and eliminate the causes of their rapid reproduction.
Planaria are harmless, non-parasitic flatworms, which often strike terror into the hearts of aquarists, because by mistake they are mistaken for parasites like leeches. They usually reach a length of 2-10 mm and are creamy white, gray or brown. Light planarias, while on the glass of an aquarium, appear translucent, and dark planarians look like tiny slugs.
Characteristic features are a V-shaped head and a slow sliding movement along the surfaces of the aquarium.
Planarium can be unintentionally added to an aquarium along with aquatic plants or live food. In the aquarium there may be a small and completely imperceptible population of planarians living in the soil or on its surface.
Sometimes their numbers become too large, and then you can see how they crawl on the front glass of the aquarium or swim freely in the water. Such rapid reproduction is an indicator of overfeeding fish.
The uneaten food is absorbed by planarians, whose population is growing at an explosive rate. It is necessary to review the mode of feeding fish and improve the quality of water, if it has suffered due to overfeeding.
The planarian problem often occurs where large fish feed on food that disintegrates in their mouths. After that, a rain of particles of food flies out of the gills and falls to the bottom.
These particles are too small to be of interest to large fish. In such cases, the matter may not be in quantity, but in the type of feed, which is the real problem.
A possible solution is to change the diet or keep fish in the aquarium that have a habit of rummaging in the ground and cleaning up everything that fell from above.
Some species of fish, such as gourami, eat planaria and thereby control their numbers. However, this method of control does not allow to avoid other hazards, in particular, pollution arising from uneaten feed.
Therefore, it should not be considered as the optimal solution to the problem.
Some aquarists deliberately launch aquatic snails into an aquarium to serve as “cleaners” and clean up food debris. Sometimes snails enter the tank randomly – usually on plants. But no matter how the snails get into the aquarium, if later they turn out to be undesirable, it is not easy to remove them from there.
This particularly applies to the viviparous snail called melania sandy Melania tuberculata. These snails live in the ground, where they can multiply very intensively, and so that the aquarist will have no idea that they are there.
The presence of a large number of snails is an indicator of an unhealthy aquarium. In order for snails to live, they must not only find enough organic matter to feed, but also consume oxygen and produce organic waste.
Some of them eat fish roe. Snails caught in the wild or caught in ornamental ponds, can bring into the aquarium many parasites for which they are intermediate owners.
The population size of snails can be kept within reasonable limits by regularly removing all the snails that can be seen. For example, you can collect them net or filter.
Large individuals can be harvested individually by hand. It is better to remove snails after turning off the light in the aquarium, since most of the snails are active at night.
Ground snails leave it at night to search for food on decorative objects and aquarium glass.
On sale there are special tools for the destruction of snails, but in aquariums inhabited by fish, their use is undesirable. Most of these shellfish products contain copper, which is poisonous to fish, so an excessive dose can be fatal.
The bodies of snails can greatly pollute the aquarium, especially where the main problems are sandy melania. Even if this chemical is applied at night, innumerable dead snails are likely to remain in the substrate.
If you are still convinced that such a tool must be used to destroy sandy snails, the fish should be transferred to another room. After that, you need to process the aquarium, then carefully clean it and reinstall it, filling it with a new substrate.
To avoid accidental entry of snails, before planting plants in an aquarium, it is perfectly acceptable to treat them with a means to destroy mollusks. Remember that during the visual inspection of plants, tiny snails can be overlooked. Do not buy fish from aquariums in which sand melania are found.
If they are in any of your aquariums, keep it in quarantine until you have completely destroyed them, because tiny newborn snails can very easily end up as “ticketless passengers” in nets, fish bags, siphon pipes and other items of equipment.
The tubife Tubifex is usually used as a live feed for fish, despite the fact that they can bring any disease into the aquarium. If you throw pipe makers into an aquarium in which there is soil, then some of them can dig into it and avoid eating. This can happen even if the fish are fed from a special feeder and they feed too many tubers at a time.
Those pipe makers who remain uneaten will eventually crawl out of the feeder and fall to the bottom. As a result, a whole colony of tubules – small red-brown worms, partially protruding from the substrate – form in the soil. The best solution is to stop feeding the fish.
When the fish get hungry due to the lack of easier prey, they will take the trouble to catch these worms and soon solve the problem themselves.