How to understand that something is wrong with fish? How to understand that there is a fish in an aquarium Gold aquarium fish.

We almost always correctly determine whether a person close to us feels good or bad, whether he is healthy or sick. This is noticeable by changes in his behavior, appearance, and obvious signs of the disease. It is also possible to distinguish a sick fish from a healthy one. To do this, you need to know exactly what you should pay attention to first.

Every self-respecting aquarist should determine the health status of a fish. Ideally, this knowledge should be obtained before adding ornamental fish to your aquarium.

Both the success of the first experience of keeping representatives of aquatic fauna and the state of the existing home aquarium world depend on this.

Indeed, you only have to make one mistake when buying a new fish, and a sick specimen can infect the pets already living in your aquarium.

And selling unhealthy fish in pet stores is not that uncommon.

Many novice aquarists think that it is very difficult to distinguish a healthy fish from a sick one, that this ability comes only with experience, after passing difficult path trial and error.

Of course, experience (often negative) contributes to the acquisition of knowledge, but even a beginner is very likely able to determine the health status of an ornamental fish. If, of course, he studies some useful information and will pay close attention to certain signs.

Behavior and appearance- these are the main criteria by which you can find out about the condition of any fish. Exactly the same as in humans.

Signs of Unhealthy Behavior

Like people, fish different types differ in their temperament. One species is characterized by hyperactivity, while others most often behave calmly and even phlegmatically. But all healthy individuals exhibit vital activity, their inherent species-specific behavior, and respond well to external stimuli (loud sounds, bright light).

• Frequent breathing is also a sign of the disease. Even if the aquarium has a normal air supply that supplies enough air to the water, a pet tries to constantly swim near the surface of the water. This course of action clearly indicates a health disorder.

• One of the signs is precisely non-standard behavior, when the fish is passive all the time or has poor coordination of movements. It can often lie motionless on the ground or constantly hide in thickets of ornamental vegetation, as if hiding from prying eyes.

• Behavior during feeding is another way to distinguish healthy fish from sick ones, since lack of appetite or complete refusal of food indicates some kind of disorder in the body.

• If fish rub their whole bodies against the decorative elements of the internal landscape of the aquarium, then this also indicates that not everything is all right with them. But here it should be borne in mind that for some species this behavior is considered the norm. Especially when they are full.

Appearance: signs of illness

Knowing in advance what a healthy fish should look like, you can with a high degree of confidence determine its well-being based on its body shape. An individual that is too thin or, on the contrary, too fat raises legitimate suspicion. The only exception is the female before spawning, when her tummy swells.

Body

There should be no bumps, ulcers or unusual bulges on the body of a healthy fish, and the scales should always be smooth and shiny. All scales fit tightly to each other. But if the scales are protruding or there are gaps or wounds in the scaly cover, then you should not buy such a specimen.

A sticky and cloudy coating on the body also indicates deviations from the normal state.

Gills

The health status of the animal is easily determined by the appearance of the gills. In healthy fish, the gill covers should open and close tightly during breathing. The gills are swollen, their lids do not close completely - this is a clear sign of the presence of the disease. Just like the very reddened gills that occur when poisoned by ammonia compounds.

Eyes and fins

The eyes can tell a lot. A healthy fish should have perfectly round eyes and a clear eye color. But cloudy eyes indicate that her condition is abnormal.

A healthy individual has even, straightened fins. Broken, frayed fins with red veins (if you look at the light) belong to a sick fish.

By the type of excrement, you can also distinguish a healthy specimen from a sick one. In a healthy individual they are short, in a patient they can be long and stretchy.

Quarantine

Of course, even if you paid attention to the presence or absence of all these signs, no one can give an absolute guarantee of the health of the newly purchased fish. The fact is that some diseases have a certain incubation period and appear at a certain time. It happens that at the time of purchase the disease has not yet manifested itself.

Well, if the fish starts to hurt in your home aquarium, then you can accurately determine its condition. Immediately isolate her (before she infects all her neighbors, if the disease is infectious) and begin treatment.

Guppies are beautiful freshwater fish. It is hardly possible to find another breed of fish that has remained loyal to both beginning and experienced aquarists for several decades. The phenomenon is explained not only by the ease of maintenance and unpretentiousness in nutrition, but also by the huge variety of colors, shapes of fins, interesting features breeding.

Guppies have strong sexual dimorphism. The male, unlike the female, has a more graceful physique, elongated fins and is more intensely colored. Guppies reach sexual maturity at the age of 3-4 months. Housing conditions have a significant impact on the reproductive functions and maturation of fish. An increase in water temperature by 2-3 degrees leads to faster metabolism and earlier puberty in guppies.

Some experts warn that stimulation methods such as water changes and increasing water temperature are only needed if labor is difficult or occurs prematurely. A decrease in temperature can significantly slow down not only the development of the reproductive system, but also lead to lethargy, decreased activity, and illness.

These cute fish are viviparous, or rather oviparous. In them, fertilization occurs internally, and fertilized eggs also develop in the female's abdomen. From a single mating, she can produce several groups of fry, so it is necessary to notice the pregnancy in time and place the female in a spawning tank so that other fish or the parents themselves do not eat the babies.

It is necessary to observe “mating courtship” so that one female is not chosen by several males, which will have a bad effect on the condition of the expectant mother and the quality of the offspring. Therefore, the ideal option is a pair of guppies that need to be isolated.

Readiness of fish for fertilization

When breeding purebred guppies or engaging in selection, it is necessary to strictly monitor the crossing of fish and correctly form pairs. And to do this, you need to determine in time the guppies’ readiness for mating.

A sign of readiness for the mating process in guppies is courtship. The male begins to “chase” the chosen one, pressing against her side with his anal fin. At this point, the aquarist must isolate the couple, since the fertilization process has already begun. In the future, placing a pregnant female in a separate vessel can be dangerous for her and her offspring, since she becomes very sensitive to changes in environmental characteristics.

These unpretentious fish can reproduce in a small container, but how better conditions, the more healthy and large offspring you can get. The “maternity hospital” should have enough space for 2 guppies. Experienced aquarists claim that from the moment the couple is isolated, the female’s pregnancy can be counted. Very rarely, a male may need 2-4 days for fertilization.

Depending on age, number of previous marks, water temperature, type of food and other characteristics, the duration of the gestation period can vary from 30 to 60 days. Normally, the period is 30 ± 5 days. A reduction or increase in gestational age may indicate a violation of the conditions of detention or problems with the health of the fish. The interval between litters can be 1-2 months.

A special feature of the livebearers is that the mark is extended over time. A fertilized fish can “give birth” to fry in groups with a time gap between births. Sometimes another male mates with the female who gave birth, and in the next generation babies will appear from both males.

Fertilization process

Sperm are introduced into the female's genital opening using the gonopodium. The formation of the copulation organ begins during puberty. Before this, there are no differences in the structure of the anal fin of the female and the male. With the onset of puberty, the rays in cross-section resemble a triangle, and later a tube.

The tube, equipped with muscle fibers, rises or falls, which facilitates the introduction of spermatophores - “packets” of sperm into the female’s body. They are partially spent on fertilizing part of the eggs, and a certain amount of seed material is stored inside the reproductive organs of the female for several months. In guppies, as a result of one insemination, from 5-6 to 11 marks often occur.

When the female is completely ready to mate, she releases environment a special secret that attracts males to her. They also have a chemical effect on the mating behavior of females. Copulin secreted by the gonads of males forces the female to take a position that is most convenient for inserting the gonopodium into the genital opening. The female's swimming in an inclined position is another sign of her readiness for copulation.

But such chemical “markers” of readiness for procreation do not replace physical stimulation. The male begins a courtship dance around the female, spreading his fins and sparkling with the bright color of his body, he quickly rushes around the chosen one. Several males can “chase” a female at once.

Interestingly, each male has his own dance, which he repeats in great detail during each mating. This mating ritual is enshrined in the genetic memory of males. If he does not “court,” the female will not allow the male to approach her, despite the chemical marks.

The female also chooses a “gentleman” based on the brightness of the color and the length of the fins. The winners are males with red coloring or red spots and long fins. They grow in males throughout their lives and indicate longevity and good health. These qualities are desirable in offspring. Thus, information about his viability as the father of numerous offspring is “encoded” in the male’s appearance.

Signs of pregnancy

By observing the behavior and appearance of the female, you can determine whether she is pregnant. Experienced aquarists note that before the appearance external signs During pregnancy, changes occur in the behavior and appetite of the female. 1.5 weeks before giving birth, there is a sharp increase in the fish’s appetite, so inexperienced guppy owners attribute the rounded abdomen to overeating.

But if you carefully monitor the female’s condition, you will notice that her tummy is getting bigger. Unlike an overfed fish, the belly is enlarged not only in the lower part, but also on the sides. When viewed from above, the rounded sides of the fish are visible. The closer to birth, the “squarer” the abdomen is, and a “prenatal” or maturity spot appears in the area of ​​the anal fin. It can be dark brown, yellowish ocher or black. Through the stretched skin of the abdomen you can see the “grain” of the spot, the so-called “eyes of the fry.”

A few hours before giving birth, the abdomen is already so large that a noticeable hollow forms between the chest and abdomen. A bulge forms in the area of ​​the anal fin. Its appearance signals that there is about a day left before the fry appear. It is worth noting that the degree of severity of the “square” abdomen and “prenatal spot” stage in some varieties of guppies is less pronounced, but the anal bulge must certainly be present.

Before giving birth, the behavior of the fish also changes. She begins to look for shelter or tries to hide among the plants. This is especially noticeable in a community aquarium - the males begin to chase the female, but she hides from them. Features are also observed in the movements - the fish hangs motionless at the surface of the water or in the middle layers, it lowers its tail.

When contractions occur, you may notice trembling of the muscles in the anal area and trembling of the caudal fin. Childbirth lasts from 3 to 5 hours. Sometimes the process stretches to 5-7 days. The number of fry in a tag depends on the size, age of the fish and the number of previous births. A first-born mother can give birth to 15-25 babies, and with repeated births their number increases. There is a recorded case where a guppy gave birth to 180 fry in one mark.

The health of the fry and female depends on:

• environmental conditions - high temperature causes premature birth and the appearance of non-viable offspring;
• food – live food contributes to the normal formation of fry and the maintenance of pregnancy. When a pregnant female is fed dry food, the fry may experience scoliosis;
• the presence of one or more males - they exhaust the female.

Sometimes a young and healthy female cannot give birth. To stimulate labor, replace settled fresh water, increase the temperature to 28-30°C, or add a young male before spawning.

Guppy pregnancy video

Caring for fry and female

After the female has fry, she must be removed or the fry placed in a container for rearing. The fry are active and immediately begin to look for shelter. Their survival depends on this, since guppies have a complete absence of parental instinct. The female perceives large fry as prey. Therefore, pebbles, artificial or live plants are placed at the bottom of the spawning tank - everything that the kids can use as shelter.

An interesting feature of guppies is that they are hermaphrodites - individuals in which the genital organs of both sexes are developed. Self-fertilization is possible in such fish. In addition, spontaneous transformation of a female, even one that has already spawned, into a male occurs. Much less often, a male turns into a female.

Guppies are interesting in terms of breeding. Behind short period they can produce several groups of fry, which is very convenient for selection. To get healthy purebred offspring, you need to know all the intricacies of breeding these amazing fish.

A useful video about treating fish that will help solve the question of what to do with a dying fish?

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How to determine that a fish is pregnant:: pregnant aquarium fish:: Breeding

How to care for pregnant guppies

How does a guppy bear its young?

How do guppies give birth?

Towards the end of the pregnancy, a week before the expected birth, the female can be transferred to a prepared maternity tank by pouring water from a common aquarium into it. In such an aquarium there is a dividing wall, so the fry will not be harmed by hungry female. On the day of pregnancy, the female cannot be transferred to such a tank, otherwise a miscarriage will occur. When the female is ready to give birth, she may swim slowly, or look for a secluded place in the aquarium. During one birth, she will produce 10-60 fry, although some mature females can give birth to up to 200 babies.

How long does labor take? Usually a few days. In 1 day, the female can bring all the fry, but it happens that only one fry per day. If the birth takes place in a community aquarium, make sure there are plenty of bushes of live plants in which the babies can save their lives. Unfortunately, the fry are clearly visible, so they become victims of their parents and their neighbors in the aquarium.

How to determine readiness for childbirth? Before this process, the female’s body trembles, she is inactive, and has no appetite (she may spit out food). If a heater is installed in the tank, the female may be near it. Also, the listed signs may indicate premature birth. During the birth itself, the female's tail trembles and she freezes for a few seconds. Live and nimble fry emerge from the anus, they immediately swim actively, beginning an independent life.

Watch how the guppy fry are born.

A female guppy can become pregnant again, even just hours after giving birth. She can store a male's sperm for one year, and up to 8 pregnancies can occur from one fertilization, in case favorable conditions in aquarium. In one life (3-5 years), a female fish can give birth to 2000 fry or more. The day before giving birth, swelling may appear near the anus; if it is not there, this is an obvious pathology.

After 2 weeks, the babies will mature and grow to 1.5-2 cm in length. At this age, you can sort fish by gender. Young females of this age can be recognized by the first sign of sexual dimorphism - they have a dark spot at the bottom of the abdomen, at the base of the anal fin. You can transplant males and females into different aquariums by pouring in their usual “old” water from the previous aquarium. In silver and light breeds of guppies, gender differences are more difficult to determine - in females there will be a barely noticeable mark on the abdomen. White spot, not black. It will be easier to find out the sex of fish at the age of 1.5 months, however late dates sorting can provoke early pregnancy.

The danger for pregnant female guppies is the disease plistophorosis. Fry can become infected from their mother. The fish looks sluggish and faded, the caudal fin moves down, the female swims at an angle of 45-60o. A sick fish may jump, trying to return to its original, normal body position, and refuse food. Plystophorosis cannot be treated, so a pregnant fish will not be able to survive. It is destroyed, and all decorations and equipment must be strictly disinfected.

Fry that receive insufficient light and protein may suffer from scoliosis. The causes of scoliosis are not well understood; sometimes this disease manifests itself in tuberculosis. It is believed that the main causes of spinal curvature are stress, injury, pathology of egg development, improper feeding of a pregnant fish, and oxygen starvation.

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How to understand that a betta fish is pregnant:: how to determine the age of a betta fish:: Breeding

How to understand that a betta fish is pregnant

Betta fish are one of the most spectacular species, which delight aquarists not only with their bright colors, bushy tail and fins, but also with their fighting spirit. However, breeding bettas requires special care, because the male will look after the eggs, and the fish become especially aggressive during this period.

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Instructions

1. To breed betta fish, select at least two fish: a male and a female. You can determine the sex of fish by comparison - males are larger, they have a large tail and a rounded fin. They behave more aggressively if you put them in front of a mirror, they begin to inflate their gills and attack the reflection. Females behave more modestly and are painted in paler shades; they always have a white spot on their abdomen. The difficulty is that some males also have a white spot, and some “hens” behave aggressively and can be very rough on their “spouse”.

2. Choose the right pair, preferably one species, for example, a female and a male veiltail. Fish no younger than 3.5 months old, but not too old, are capable of breeding. Before planning spawning, it is better to place them in different reservoirs for a week and feed them with live food: bloodworms or coretra, it contains many nutrients.

3. To determine if your betta fish is pregnant, simply watch it. In fact, the female produces eggs constantly, so we cannot talk about her pregnancy as a temporary period. For an aquarist, such a concept as a cockerel’s readiness to spawn is much more important. The abdomen enlarges slightly, the stripes turn from horizontal to vertical and very clear. In light-colored individuals, the eggs may be visible through the abdomen. Behavior also changes: females begin to inflate their gills, flirt and swim next to the male.

5. Please note main role A male cockerel plays in building the nest. He builds a foam nest on the surface of the water, then pushes the female towards the nest, presses on her abdomen and the eggs slip out. He then fertilizes them and places them in the nest. After the “birth”, the male begins to push the female away from the nest - at this moment it is better to put her in another body of water, she will no longer care for the clutch. When the fry hatch and begin to swim, it should also be removed.

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How to understand that a guppy is pregnant:: how to understand that a guppy is about to give birth:: Aquarium fish

How to tell if a guppy is pregnant

Guppy is a freshwater fish that belongs to the Petsiliev family. It is considered quite unpretentious, as well as popular among all aquarium fish. It should be noted that every breeder should have an idea of ​​how to determine if a female guppy is pregnant. This knowledge will help to timely create certain conditions for a female expecting offspring.

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Instructions

1. As a rule, a guppy's pregnancy is determined by the shape of its abdomen. The fact is that the female bearing the offspring has a rounded, voluminous abdomen, which immediately before giving birth takes on a slightly rectangular shape. Sometimes fry can be observed through the gaps, and closer to labor, the guppies develop a dark birth spot, localized on the abdomen. It must be taken into account that the shape of the fish’s head during this period begins to appear graceful due to its voluminous belly. In addition, a pregnant female is distinguished by a peaceful and calm behavior.

2. Often, before throwing fry, the back of the guppies' belly becomes dark. If there are only fish of this family in the aquarium, and there are also many shelters in the form of stones, snags and algae, then the female does not need to be removed. However, if there are other fish in the aquarium, the guppy bearing offspring must be removed for the period of throwing, and then released back. It is important to remember that the fry must be kept in a separate container.

3. When placing a pregnant female, you need to take into account that she is capable of eating her fry. Thus, it is advisable to take care in advance of purchasing plants with which they can hide from the mother, who is temporarily next to the offspring. The number of fry born to a female directly depends on her age. A young fish can produce up to ten offspring, while an old one can produce hundreds of fry. In order for the offspring to have beautiful colors and develop quickly, they should be fed a variety of foods three times a day.

4. Generally, a guppy's pregnancy lasts forty days. During the first week after birth, the fry live in a nursery. Then they are transplanted into the most spacious containers. Already in a month you can notice distinctive features, allowing you to determine the sex of the fry. In females, a birthmark appears near the anus. At three months, males change the so-called anal fin into a gonopodium. It should be taken into account that in order to prevent the reproduction of guppies, it is advisable to timely distribute young offspring by gender and be sure to keep them separately. IN winter time it is necessary to maintain the water temperature, which should be eighteen degrees Celsius. Such actions will not only help avoid unnecessary spawning, but will also allow the female to take a break from labor.

Aquarium fish are wonderful pets that do not require extensive care. They are distinguished by a wide variety of types and colors, and an aquarium can adequately decorate any home. However, sometimes fish are susceptible to stress and illness. Proper care of your fish and aquarium and the ability to recognize warning signs early will help you keep your pets healthy and cope with possible problems.

Steps

Part 1

Watch the fish. Pay attention to how they swim, breathe, eat, and interact with other aquarium inhabitants. Know what the norm is so you can recognize deviations from it. Healthy fish have a good appetite and actively swim in the aquarium.

Find out about various types aquarium fish. For each type of fish healthy life Certain aquarium sizes, temperatures, care, equipment and food are required. Freshwater and sea ​​fish require various conditions content.

Make sure your fish are not stressed. The best way Keeping your fish healthy means providing them with conditions that do not cause stress. Stress weakens the fish's immune system, which can cause them to get sick. Prevent stress proper care and care to protect your pets from various diseases.

• Keep an eye on your aquarium and do partial water changes regularly. Change about a quarter of the water in the aquarium every two weeks.
• Give your fish nutritious and varied food. Most fish remain healthy and even thrive when fed processed food in the form of flakes or pellets. Diversify your pets' diet so they get extra nutrients and dietary fiber: for this, give them frozen or dried red worms, live or frozen plankton and some vegetables.
• Don't overfeed your fish. Give the fish as much as they can eat in three minutes. Excess food will not only pollute the water, but will also negatively affect the health of the fish.
• Check that the filtration system is working effectively. Filters remove toxins such as ammonia and nitrites from water.
• Make sure your fish have enough space to live comfortably. Do not overpopulate the aquarium. Observe next rule: for every 2.5 centimeters of fish length there should be at least 4 liters of water.
• Place in one aquarium fish species that get along well with each other. You don't want the fish to compete with each other, fight and eat each other. A peaceful fish will experience stress if it is introduced to aggressive species or those that use a completely different sign language to communicate.

1. Monitor the water temperature in the aquarium. The temperature must correspond to the needs of this type of fish. Too cold or warm water will cause stress in the fish. For example, goldfish prefer temperatures no higher than 21°C, while most tropical fish species require temperatures between 23-26°C.

2. Buy your fish from a reputable pet store. If the fish lived in a crowded and dirty aquarium, then they were stressed all the time, and when they move into your aquarium, they can infect other fish with diseases. It's better to spend a little O a larger amount for healthy fish and be sure that they will not die within the next month.

   • In a store, fish should live in clean aquarium, be active, have bright color and don't feel stressed.
   • The pet store must have a certificate for the fish it sells and provide a full refund if the fish dies within a few days of purchase.
   • Sellers must know everything they need to know about the fish they sell, as well as the rules for caring for the aquarium, its size, inhabitants, diseases, and so on.
   • As a rule, it is better to go to a store that specializes in aquariums and aquarium fish.

3. Cure other diseases. You can try to combat the symptoms using the above methods. Often, more frequent water changes and careful aquarium care can get rid of the disease within a few days or weeks.

   • If your fish has a swollen belly, it may suffer from constipation. In this case, try using frozen peas. Peel it, defrost it and cut it into tiny pieces. Give a few pieces to the fish, then do not feed it for several days. Instead of peas, you can give your fish fresh, frozen or dried daphnia.

How to determine when buying a fish whether it is healthy or sick.

Sick fish can be distinguished from healthy fish by many characteristics. The disease is primarily indicated by appearance: dull color, pressed, as if glued fins, fringe on them, sometimes barely noticeable, retracted or, conversely, swollen belly, excessive thinness. Ruffling of the scales and damage may be observed. In some cases, the gill covers are raised or damaged. Clear signs diseases - ulcers, various kinds of rashes on the body, cotton wool-like plaque in certain areas, the presence of cataracts, bulging eyes, hemorrhages, etc. Excrement often looks like long mucous threads. Sick fish also differ in behavior: they often stand in one place, sway, hide in corners, itch against the bottom, plants, sometimes move jerkily, and rotate in one place.

Why do fish get sick?

Diseases of aquarium fish usually occur due to keeping them in unfavorable conditions. Pisces weaken and are easily susceptible to disease. TO unfavorable conditions relate: low temperature water or its sharp fluctuations, excess or lack of lighting, unsuitable for this species chemical composition water, the presence of toxic substances in water, etc. They have a bad effect on fish sudden changes environment parameters: replacement immediately large quantity water, transplanting fish into an aquarium with other conditions, etc. The cause of the disease is often improper feeding: lack or excess of food, monotonous or poor-quality food, inadequate diet, inconsistency of its composition with the needs of fish of a given species (for example, lack of plant food in the diet of herbivorous fish) . And of course, diseases can be caused by the introduction of infectious agents from natural bodies of water along with live food and plants, as well as due to the placement of fish in an aquarium without prior quarantine. If fish are kept in an aquarium with an established biological regime, on nutritious food, they, as a rule, do not get sick, although pathogens may be present in the aquarium (the so-called “dormant” infection).

How to understand that the fish is sick.

Nonspecific signs of disease in fish.

These signs may appear separately or in combination. They only matter if they are a deviation from the norm.
- Loss or decreased appetite.
- Abnormal behavior of one type or another.
- Change in color.
- Compressed fins.
- The fish is hiding.
- Lethargy.
- Breathing disorder.
- Abnormal swimming.
- Fish excrement takes on the appearance of long threads hanging at the anus.
Fish exhibiting any of these signs should be closely monitored for additional signs of any specific disease. It is necessary to check the concentration of nitrogen-containing substances, as well as other water parameters such as temperature and pH.
It is not always possible to accurately diagnose and identify a specific fish disease. In such situations, the measures taken will depend on the circumstances. There is no point in treating an unknown disease by arbitrarily using chemicals. medicines in the hope of accidentally getting on the right medicine. Many medications are toxic to fish to one degree or another and can cause aggravation. The combination of different chemical drugs (when different drugs are used sequentially without destroying traces of previous treatment by partial replacement of water or neutralization) is a very effective method poison the fish.
If a diagnosis cannot be made based on external signs of the disease, samples will have to be taken for laboratory analysis. To clarify the situation, either samples may be required aquarium water(these are useful if you suspect poisoning, but the cause is not clear), or biological material obtained from opening fish. In both cases, the tests must be performed with the help of a veterinarian or fish health consultant.

Nonspecific signs of irritation in fish.

Fish diseases caused by unfavorable conditions.

In addition to direct effects, unfavorable conditions weaken the fish’s body and open the door to infectious diseases. Fish most often get sick due to prolonged exposure to low temperatures. This usually happens in spring and autumn - during periods when the heating season has stopped or has not begun. An increase in water temperature to 32-35° usually does not have a harmful effect on many species of fish. At very high temperature the fish, as a rule, begin to rush about in a vertical plane, sometimes even trying to jump out of the water. Sudden temperature fluctuations can also cause illness.
Lack of oxygen can lead to death from suffocation. It is usually determined by the behavior of fish, which rise to the surface of the water and swallow air bubbles. The situation is worse if there are no noticeable signs of oxygen deficiency, then proper measures are not taken and the fish gradually weaken. In this case, young fish become “tight”. Various types of diseases and death due to insufficient oxygen occur more likely at high water temperatures. Diseases can occur when kept in water that is too acidic or too alkaline for a given type of fish, as well as in water that is too soft or hard.
For a number of fish species, excessive loading of water with various organic residues is contraindicated. On the one hand, during the decomposition of residues, oxygen is consumed and its deficiency is detected, on the other hand, decomposition products are formed, for example, nitrogen and sulfur compounds, which are themselves poisonous,
Humic acids reduce the pH and hardness of water, making living conditions unsuitable for many species, while other fish can be kept long time under the same conditions without visible harm.

Fish diseases caused by improper feeding.

Fasting adult fish, sometimes even for a long period, usually does not lead to visible negative results. In contrast, for fry in the first periods of feeding it is very great importance both quantity and quality of feed. As a result of insufficient feeding of the fry, as well as in the case of a deficiency of calcium or other components, fish often grow with pathological changes in the structure of various organs, primarily this is reflected in the curvature of the caudal peduncle. In some species, insufficient feeding of grown fry is compensated by further accelerated growth. However, there are cases when fry, after a long period of fasting, completely refuse food and die from exhaustion. For the most part, grown fish that did not receive food in sufficient quantities at one or another (especially early) stage of development find themselves “delayed.” Many of them are subsequently unsuitable for breeding.
Obesity of the viscera is common cause death of adult fish in aquariums. This fish disease can almost entirely be attributed to their captivity. Limited movement and abundant regular feeding are the main reasons for the deposition of unspent substances in the body of adult fish. When keeping many animals in captivity, one day a week is usually “hungry”; Maybe we should do the same with fish. The deposition of fat in the liver leads to its degeneration and causes severe metabolic disturbances. Due to obesity in the testes and ovaries, fish can become completely infertile. Obesity of the viscera greatly weakens the body of fish, making them susceptible to infectious diseases, primarily to infectious dropsy of the abdomen. It is usually impossible to cure fish with fatty viscera.
Inflammation of the stomach and intestines often occurs in adult fish in an aquarium as a result of prolonged feeding of monotonous food, especially in cases where it is very concentrated. Inflammatory process begins, in particular, when feeding enchytraeus, often with dry food (as a result of a lack of vitamins, proteins or fats), as well as bloodworms or tubifex taken from reservoirs contaminated with various types of waste. Sometimes there are difficult to explain cases of poisoning by completely benign bloodworms. For inflammation gastrointestinal tract The fish's appetite, as a rule, does not disappear, their movements become lazier, and the color darkens somewhat. If at the same time the abdomen swells slightly, then inflammation of the stomach can be suspected. When the intestines become inflamed, the anus becomes reddish, and the excrement becomes mucous, bloody, and thread-like. Inflammation of the stomach and intestines weakens fish and opens the way to many infectious diseases.

Poisoning. Poisoning by insecticides, etc.

Chlorine in tap water for fish and plants.

In order to combat microorganisms, chlorine gas is added to tap water. As a result, hydrochloric acid and perchloric acid are formed, the latter decomposes in the light into hydrochloric acid and oxygen. This oxygen is very active at the moment of its occurrence and, with its strong oxidizing effect, kills bacteria and other microorganisms. Tap water usually contains a little chlorine (0.1-0.4 mg/l), but in special cases, particularly in spring, the chlorine content in the water rises to 0.4-0.5 mg/l (at this time it smells like chlorine ) and has a harmful effect on fish, and sometimes kills them. First of all toxic effect affects the gills, they become sick, their tissue is destroyed, then the fins and the whole body are damaged. For aquatic plants chlorine is harmless.
Chlorine can be removed from water by standing for 1-2 days or by vigorously blowing for several hours. When pasteurizing water for 30-40 minutes, chlorine is also completely removed.

Wounds inflicted by fish on each other.

In aquarium practice, one very often encounters such cases when fish injure each other. Many large cichlids, labyrinths and some spawn-marking carp-toothed and other fish damage, to a greater or lesser extent, representatives of both their own and other fish species. Damaged areas of the body and fins regenerate at high speed without harm to the victims (of course, if the damage did not affect vital organs). In these cases, usually no infection of any kind affects the wounded fish.