Fish are dying in the aquarium, what should I do? Why fish die in an aquarium and what needs to be done. Lack of oxygen in aquarium water

If fish die in an aquarium, it is very important to determine the cause. This can happen even if all the conditions for its content are met. Aquarium keeping is a rather complex type of activity, which involves the correct modeling of a favorable ecosystem in an artificial reservoir (aquarium).

Fish can die due to injuries received in fights. Peaceful species very often suffer from constant attacks from aggressive neighbors. In addition, larger species of fish try to eat fry or small inhabitants of the aquarium. Some small fish attach themselves to the body of others, causing their death. The strong eat the weak. To avoid this, keep fish species that are compatible with each other in the aquarium.

Non-compliance of the parameters of the aquatic environment with the standards, heavily polluted water in the tank, violation of the temperature regime, and the presence of a large number of organic compounds can provoke the death of all the fish at once. For example, hypothermia is dangerous for calico. Goldfish die due to poisoning with nitrogen compounds.

To avoid this, create optimal conditions, taking into account the species characteristics of the fish. It is necessary to purchase high-quality equipment, aquarium systems, and constantly monitor, using special test systems, the parameters of the aquatic environment in the tank.

Nitrogen poisoning

If you notice that fish in your aquarium have begun to die, one of the possible reasons is poisoning with nitrogen compounds. During the life of aquarium fish, a large amount of organic matter accumulates in the water - nitrates, nitrites, ammonia.

During the day, the number of bowel movements is 1/3 of the total weight of the fish.

Without exception, all nitrogen compounds are very toxic and poisonous to the inhabitants of the aquarium. Ammonia is especially dangerous. Its excess in the aquatic environment can cause mass death of the entire aquarium population.

Breakdown of filtration systems, overcrowding in the aquarium, poor aeration, overfeeding are factors that contribute to an increase in nitrogen in the aquatic environment.

You can determine excess nitrogen compounds in an aquarium by the state of the water, namely by smell and color. If the aquatic environment is cloudy, or an unpleasant putrid odor is coming from the aquarium, this means that measures need to be taken to normalize the condition of the aquatic environment. Even if the water is visually clean, but there is a smell, this means that the ammonia process has started.

To normalize water parameters and eliminate ammonia compounds, replace ¼ of the water in the aquarium and increase aeration. You only need to add water that has been standing for 24 hours.

Lack of oxygen

Aquarium fish can die due to lack of oxygen in the water. Most often, this situation occurs due to a breakdown of the aeration system, as well as due to overcrowding in the aquarium.

You can understand that fish lack O2 by their behavior. Pets become inactive, swim sluggishly with widely spaced gills, stay in the upper layers of the reservoir, and breathe heavily.

Lack of oxygen leads to oxygen starvation and can cause gas embolism. To avoid fish death due to suffocation, purchase a high-quality, powerful aquatic system. You can also plant live plants in the aquarium, as they saturate the water with oxygen.

Fish diseases

Aquarists should know the main fish diseases and their symptoms. The choice of treatment methods depends on the degree and severity of the disease.

Having noticed that the fish is sick, it needs to be placed in a separate tank as quickly as possible. This will avoid mass infection and death of aquarium inhabitants. It is necessary to remove all carriers of infection, infected or suspicious individuals from the aquarium, so as not to expose the rest of the fish to danger.

If you don’t know how to treat your fish, consult a veterinarian or experienced aquarists. There are no universal cures, but if the fish is sick, you need to increase the aeration of the water, raise the temperature of the aquatic environment, and replace part of the water daily. Antibacterial agents are added to the water. In addition, you need to boil the soil, disinfect the decor, rinse the algae well, and clean the filters. It is necessary to keep the fish in the aquarium until the symptoms of the disease completely disappear and the condition returns to normal.

Procedure

If fish begin to die en masse, as already noted, it is necessary to establish the cause. Carefully examine the dead specimen. Analyze what could have caused it, determine why the fish began to die. Aquarium inhabitants can also die due to stress, overfeeding, obesity, injuries, bruises, congenital and genetic pathologies.

If the fish has died, it must be removed from the aquarium immediately. Tropical fish decompose very quickly, which leads to an increase in the number of bacteria in the aquatic environment.

If the cause is illness, provide appropriate treatment. Regarding the choice of treatment method, consult your veterinarian.

If the reason is a violation of water parameters, you need to bring them back to normal as soon as possible. Purchase special test systems. Analyze test scores. Measure pH values daily and monitor temperature conditions.

If the fish start dying suddenly, the water parameters are normal, but you don’t know what the reason is and why your pets are dying, we recommend consulting with experienced aquarists or a veterinarian, and asking questions on thematic forums.

Content:

Aquarium fish are popular and affordable pets. They are pleasant to care for, they please the eye and calm the nerves. But sometimes the fish cause trouble. Why do fish die in an aquarium if the water is clean, feeding is regular, filtration and air compressor are working without interruption? Solving this problem requires an integrated approach.

Stress due to maladjustment

Aquarium pets are sensitive to changes in the parameters of the environment in which they live. Therefore, by transplanting new fish from a bag of store-bought water into your aquarium, you are putting them in mortal danger.

To properly adapt purchased fish to new conditions, you need to:

pour water and fish from the pet store into a large vessel;
every 10-20 minutes add a little water from your aquarium to the vessel (no more than 5% of the existing volume);
When the proportion of aquarium water in the vessel reaches 70%, transfer the newcomers to the aquarium.

ATTENTION: Fish can die from an immediate increase in water acidity. A change in acidity of just one unit can be disastrous.

Sudden water change

Tap water is not the best environment for keeping aquarium fish. It contains chlorine, and in large cities it often switches from desalinated to artesian and back. Water from different sources has different hardness. A sharp change in water hardness during replacement can lead to mass death of aquarium inhabitants. Trouble can be recognized by changes in the behavior of the fish, which begin to rush around the aquarium in panic.

You can save your pets. To do this you should:

leave water to change for at least 24 hours;
change no more than 30% of the water each time;
purify water using a carbon filter;
use chemical water softeners.

Overpopulation of the aquarium

In overcrowded aquariums, fish can die much more often than in reservoirs with a small or medium number of inhabitants. The reason lies in the waste products of fish, which, when decomposed, form toxic nitrogen compounds. An excess of such organic substances can cause mass death of fish.

You can recognize an excess of toxic nitrogen compounds by the following signs:

the water becomes cloudy, the smell of rot appears;
The water remains clean, but has a distinct ammonia odor.

If you notice these signs, take the following measures:

measure the level of nitrite and ammonium in aquarium water using special tests;
make sure the filter is working properly;
For several days in a row, change up to 1/4 of the water in the aquarium.

Oxygen deficiency

Many aquarium fish get oxygen from water. If there is no air compressor in the aquarium, the pets will experience oxygen deficiency and may die. When fish lack oxygen, they stand for a long time at the surface of the reservoir and swallow air.

To prevent fish from dying from oxygen deficiency, it is necessary:

equip the aquarium with an air compressor;
do not turn off the compressor at night, keep it in working condition 24 hours a day;
Do not allow a sharp increase in the temperature of the water in the aquarium.

IMPORTANT: The risk of fish death increases with rapid heating of the water in the aquarium, as well as at night, when algae do not produce oxygen, but switch to consuming it.

Fish diseases

New fish (seemingly healthy) can be carriers of dangerous diseases that can destroy the entire population of your aquarium. Over time, such pets show characteristic signs of the disease, their condition worsens and ends in death.

To prevent new fish from infecting your pets, you must:

carry out preventive treatment for newcomers;
quarantine infected individuals;
increase water aeration while simultaneously increasing its temperature;
If there are obvious signs of the disease, carry out several water changes (10% per day).

REFERENCE: Most often, tropical fish are the source of dangerous diseases. Only laboratory testing can detect the presence of the disease. Therefore, it is better to buy fish from trusted suppliers.

Aggression of tank neighbors

Some aquarium inhabitants are aggressors. Large fish, as a rule, absorb small neighbors. Predatory fish happily chase their herbivorous counterparts and bite off the tips of their tails. There are species of fish that attach themselves to slow-moving neighbors and cause significant harm to their health.

To avoid aggression between the inhabitants of the aquarium, you must:

competently select the population of your reservoir;
When identifying incompatible fish species, isolate them from each other.

It is very unpleasant when fish begin to die in an aquarium. It would seem that everything was done correctly: clean water was poured, the aquarium equipment was working, the fish received food in a timely manner. Despite this, living creatures die. Unfortunately, this situation occurs quite often among beginners in the aquarium business, which is why it is necessary to arm yourself with knowledge about the causes of this phenomenon.

Every novice aquarist should understand the following in advance: if conditions in a water house are created for its inhabitants as close as possible to their natural habitat, then they will not get sick, much less die.

At the very least, the risk of death will be minimized.

Practice shows that in the vast majority of cases, the death of fish is not caused by any external diseases, but by errors in maintenance, illiteracy and carelessness of their owners. There are various reasons for this unfortunate phenomenon or a whole combination of reasons and factors that should be considered in detail.

Nitrogen poisoning

Nitrogen poisoning is the most common problem. It often concerns beginners who have no experience in dealing with aquarium animals. The fact is that they try to feed their pets to their fullest, forgetting that at the same time the amount of waste increases. According to the simplest calculations, each fish leaves excrement equal to 1/3 of its weight per day. However, not everyone knows that in the process of oxidation and decomposition, nitrogen compounds appear, consisting of:

Ammonium;
Nitrates;
Nitrites.

All these substances have in common their toxicity. The most dangerous of them is considered to be ammonium, an excess of which will be the main cause of death of all inhabitants of the reservoir. This happens most often in recently launched aquariums. It is the first week after the start that becomes critical. There are two options for increasing the amount of these substances in aqua:

Increase in the number of residents;
Filter failure;
Excessive amount of feed.

You can determine the excess by the state of the water, more precisely by the smell and color. If you notice darkening of the water and a rotten smell, then the process of increasing ammonium in the water has begun. It happens that upon visual inspection, the water in the fish house is crystal clear, but the smell makes you wonder.

To confirm your suspicions, ask for special chemical tests at pet stores. With their help, you can easily measure the level of ammonium. True, it is worth noting the high cost of the tests, but for a novice aquarist they are very necessary if you do not want to lose all your pets in a couple of days. If the situation is corrected in time, a fatal outcome can be avoided.

How to lower ammonia levels:

Daily ¼ water change
The water must stand for at least a day;
Checking the filter and filter element for serviceability.

Water temperature

The death of fish can also occur due to a decrease or increase in the temperature of the aquatic environment. The opinion that a deviation from a certain temperature regime by 2-3 degrees in one direction or another will not in any way affect the health of aquarium pets is deeply erroneous.

If the temperature drops, there is a danger of death from a cold, and if it rises, the fish may die from lack of oxygen.

Lack of oxygen as a negative factor

Fish are known to breathe air dissolved in water, and they can suffocate if there is too little of it in the water. Although such cases are very rare, they do occur.

As a rule, even beginners first purchase all the equipment necessary to operate a home aqua system.

And very often, when buying a fairly powerful filter, they trust it not only with water purification, but also with its aeration and mixing.

Still, experts recommend separating these two functions and ensuring constant operation of the air compressor

Fish diseases

No one wants to blame themselves, so novice breeders blame illness for everything. Unscrupulous sellers only reinforce their doubts, since their goal is to sell expensive medicine and make money. However, do not rush for a panacea; carefully study all possible causes of death.

Diseases can only be blamed if the symptoms have been observed for a long time. The fish faded away gradually, and did not just die in an instant, for no apparent reason. Most often, the disease is brought into the aquarium along with new residents or plants. Death can occur due to a malfunctioning heating element in cold weather.

When going to pet stores, you must be aware of what exactly you need medicine for. Each drug is aimed at a specific disease. There are no universal cures! If possible, consult with an experienced aquarist or ask a question on the forum; knowledgeable people will tell you what to do in such a situation.

Of course, disease cannot kill healthy fish. Why do fish die in an aquarium? If death occurs, it means that immunity has already been undermined. Most likely, the first two errors occurred. Do not rush to launch new residents, no matter how beautiful they are.

What to do to protect your aquarium:

Organize quarantine for new residents;
Sanitize your fish or plants.

What to do if there is a disease in the aquarium:

Change a tenth of the water daily;
Increase the temperature;
Increase aeration;
Remove disease carriers and those who are clearly infected.

Remember what kind of fish you launched at home last. Individuals brought from other countries can be carriers of rare diseases, which are sometimes not possible to detect and classify on their own.

O2 deficiency

This option is the rarest of all. The oxygen saturation of a fish house is always adequately assessed even by novice aquarists. The first thing everyone does is buy a compressor. With it there is no fear of fish suffocating.

The only possible option is an increase in temperature and, as a result, a decrease in oxygen in the water. This can happen at night, when plants switch from producing oxygen to absorbing it. To avoid this, do not turn off the compressor at night.

Aggressive neighbors

Before you go to the store for pets, think through to the smallest detail: will several species be able to get along in one fish house? You should not count on the seller’s competence, since his main goal is to sell as much product as possible.

A few fundamental rules:

Big fish always try to eat small ones (even in the case of herbivorous species);
Many succumb to intraspecific aggression;
Some are able to attach themselves to small neighbors, which ultimately results in death;
The strong always eat the weak;
Buy only those fish that you are sure are peaceful.

Unfortunately, it is impossible to determine why the fish are dying. The death of a pet can happen even among experienced breeders. Treat your fish carefully, and you will definitely notice a change in behavior and eliminate the cause of concern in time. More often than not, fish die in an aquarium due to oversight, and not due to other criteria.

What to do if you find dead fish in the walls of the aquarium?

Take a closer look at the number of fish in the tank. Count them in the morning and during feeding hours. What is their condition, are they getting food well? Are there any fish that refuse food? Is it possible for one of the fish to have bloating? If you do not find any fish, check all corners of the aquarium by lifting the lid. Inspect the plants, caves and all the decorations. If after a few days the dead fish has not floated to the surface, it may have been harmed by a neighbor in the aquarium, and you are unlikely to find it again. Sometimes fish get caught in an unprotected filter and die there. In any case, continue searching until you find visible reasons for the disappearance.
Fish that have died in the aquarium must be removed from it. Tropical fish species quickly rot due to elevated water temperatures. In such an environment, bacteria multiply quickly, the water becomes cloudy, and an unpleasant odor appears, which can infect other pets.
It is necessary to inspect the dead fish. You must understand why she died in the aquarium. Put medical gloves on your hands. If the body is not completely decomposed, look at the condition of the fins, scales, and the condition of the abdominal cavity. Perhaps there will be wounds on the body or signs that she suffered from unkind neighbors. If the belly is very swollen, the eyes are bulging, the scales are covered with plaque or spots, this means that the pet has suffered from illness or poisoning. After inspection, the gloves should be discarded.

Check water parameters. Water is often the main cause of deterioration in fish health. Take tests with indicators and make the necessary measurements. The increased content of ammonia, nitrates, and heavy metals in the water leads to pets quickly dying. If the aquarium has a decorative element made of iron, zinc, or copper, this is another indicator. Some fish do not tolerate metal well and die suddenly.
After the test results, draw conclusions. The test will show two results - either everything is fine in your aquarium, or the water is dirty and contains an excess of toxic substances. In the second case, you need to turn on powerful filtration and replace 25% of the aquarium water with clean and infused water. There is no need to change water parameters abruptly; this can harm living fish.
But if the water is in good condition, there could be a number of other reasons why the fish died. Sometimes aquarium pets die from hunger, overeating, illness, severe stress, bruises received after being attacked by other fish, or age. If fish die suddenly, you need to do everything necessary to keep others alive. Contact your veterinarian if no obvious cause of your pet's death is found.

The desire to penetrate the mysterious beautiful water world is understandable to everyone. But caring for an aquarium is quite a responsible and troublesome task. Therefore, before taking on such responsibility, you should seriously prepare for this. Simply purchasing an aquarium, filling it with water, introducing pets and feeding them from time to time will not work. Indeed, as a result of improper care, the aquatic fauna will die.

The first cause of fish death is poor water quality.

This includes:

chemical poisoning;
changes in water temperature;
lack of oxygen.

This does not mean that the aquarium water is cloudy or heavily polluted. It can be crystal clear, but poisoned by toxic chemicals resulting from the activity of underwater fauna.

Chemical poisoning

The whole point is nitrogen compounds: ammonium, ammonia, various nitrates. Such toxins will constantly be present in the aquarium, because pets leave a lot of waste every day, which constantly decomposes. Therefore, a visually clean underwater world is often accompanied by a rotten smell, which indicates an increased concentration of harmful nitrogen compounds.

The smell is especially noticeable if the aquarium contains many individuals, and the water purification system does not process toxins. As a result, pets are poisoned and die.

This state of water occurs under the following circumstances:

favorable ecology has not been achieved in the new aquarium;
beneficial microorganisms that convert harmful substances into neutral ones do not work efficiently enough;
new individuals are introduced into a balanced habitat;
overcrowding of the home aquarium;
failed biofilter;
improper cleaning and maintenance of the biofilter, which caused the destruction of the colony of beneficial bacteria.

To prevent the death of underwater fauna, it is necessary to prevent poisoning of the habitat:

replace some volume of water;
purchase a new biofilter;
place the fish in different aquariums.

Fluctuations in water temperature

Pets can die as a result of an increase or decrease in water temperature. The fact that a change in the temperature environment by a few degrees will not affect the health of the inhabitants of the aquarium is fundamentally wrong.

If sharply reduce temperature, the fish may catch a cold and die.

Wherein sharp increase will lead to a lack of oxygen, which will also cause the rapid death of pets.

Lack of oxygen

Fish are known to inhale air dissolved in water, and they can suffocate if there is not enough oxygen. Although such cases are encountered extremely rarely.

Basically, even inexperienced aquarists buy special equipment for the proper functioning of the home system. And often, when purchasing a powerful, reliable filter, they entrust it with not only water purification, but also its mixing and aeration.

Incorrect adaptation to new water

Often, the water in which the fish lived in a pet store can differ significantly in temperature and from home water. Almost no store systematically replaces fluids, as happens at home.

If new pets are immediately placed in a home aquarium without appropriate adaptation, they will simply die within a day or week. To eliminate this incident, when purchasing a fish, be sure to check the parameters of the water in which it was located. Knowing the parameters, guide and adapt the fish to the new water.

Read more about why water tests are needed and how to use them:

Feeding

The second, but no less important reason for the death of fish is feeding.

These include:

inadequate quality of feed;
overfeeding;
lack of food.

Diseases

The third and most important cause of death for aquarium pets is disease.

This includes:

Diseases as a result of decreased immunity due to poor water, incorrect adaptation or improper diet. Before resorting to the use of any drugs, make sure that all causes have been eliminated.
Diseases that could be carried by sick fish. You should be especially careful when handling imported fish. Before being placed in an aquarium, they must be examined for the presence of diseases and dangerous bacteria that can cause the death of other inhabitants of the aquatic world.

Fish incompatibility

The fourth reason for death is the incompatibility of aquarium species.

Very often, new aquarists place pets of different species, often incompatible with each other, into one aquarium. So, for example, large enough individuals, despite the fact that they feed on grass, can absorb their neighbors.

In addition, there are cases when aquatic fauna, under conditions of stimulation of spawning, exterminates its “friends”. Which can cause the death of small individuals. To prevent such actions, incompatible fish species should not be kept in the same tank. Be sure to look at it, and you will avoid this problem.

In order not to lose your pets, you should follow a few experienced recommendations:

You cannot introduce predatory species into the aquarium among peaceful inhabitants.
There is no need to significantly increase the population density. One medium-sized fish requires about 5 liters of water.
It is not recommended to place inhabitants with different behavior and habits (little mobile and quite active) in a glass vessel. Fish for a small “house” should be similar in character.
Population should be carried out evenly.

You can watch a video about why fish die:

Sometimes it may seem like you are following all the recommendations, but despite this, the number of pets is decreasing. So don't give up and find out the cause of the problem. A responsible approach will help ensure a long life for the fish in your underwater kingdom.

The appearance of dead fish is a common problem. Most often, fish die in novice aquarists due to improper maintenance. If conditions are created for the inhabitants that are as close to natural as possible, they will feel good and be active.

Death does not occur for no apparent reason. It is possible to identify what caused it by external examination. If you find dead fish in the aquarium, you should:

Remove dead body. If this is not done in time, decomposition and poisoning of the aquatic environment and its inhabitants will begin.
Assess the integrity of scales, fins and tail, the appearance of the belly and eyes. An examination may indicate that she was injured by neighbors, poisoning or illness.
Check the water using tests. Drip tests will provide an accurate result; they are the ones you should pay special attention to. Perhaps the content of ammonia and other harmful substances in the water is exceeded.
Inspect the aquarium and count the number of inhabitants, make sure that they are all healthy.

Why can a fish die in an aquarium?

The reasons why fish die are different, and often it depends on the conditions of detention. Sometimes several factors lead to the death of aquarium inhabitants at once.

Poor health of fish, which can lead to death, is promoted by:

lack of oxygen;
overfeeding;
sudden change in water parameters.

It is important to pay attention to the ability to get along with each other. The reason why fish die may also be due to an error in the selection of neighbors.

Nitrogen

Poisoning by nitrogenous compounds is a common cause of death. Waste products and uneaten food saturate the water with toxic nitrogen, which kills fish and other inhabitants. Increased levels of harmful substances are detected by special tests that are sold in pet stores. A rotten smell and cloudiness are also signs of poisoned water.

If dangerous chemicals are detected in the aquatic environment, the inhabitants should be immediately transplanted into a clean container. It is desirable that the liquid is settled and the temperature coincides with the one in which they live. After this, the tank is cleaned and the water is replaced up to 25%, filtration and aeration are enhanced. Special carbon is added to the filter.

Water temperature

If the temperature is too high or low (25 degrees is optimal), the fish become lethargic and in some cases die. In summer, the liquid heats up, the oxygen content in the water drops, and the aquarium population suffocates.

You should check the serviceability of the compressor, and also reduce the temperature of the water environment. Sometimes a regular air conditioner is enough to cope with the stuffiness of the room, thereby cooling the water. You can also use frozen bottled water, but you will need to constantly replace the ice. In addition, this provokes sudden temperature changes, which is undesirable.

Water quality

Chemicals must comply with acceptable standards. Some breeds die from high levels of iron, copper or zinc, so metal decorations will have a detrimental effect on them. The water should be soft or moderately hard, the acidity level should be neutral. Care must be taken to ensure that there is no appearance or smell of rot.

Adaptation

Water parameters should not be changed abruptly, as this will cause stress to residents. Sometimes rapid adaptation leads to death. You need to settle in stages:

First, the new arrivals adapt to the temperature in the vessel. To do this, the bag of fish is immersed in the aquarium for at least 15 minutes.
A small amount of aquarium water is added to the bag.
After 15–20 minutes, you can add a little more water to the package.
Adding liquid at the indicated time intervals is carried out at least three times.

Lack of oxygen

A common reason why fish die is lack of oxygen. It occurs not only as a result of rising temperatures, but also from the growth of algae, changes in the bacterial film above the surface, outbreaks of ciliates and other organisms.

If there is a lack of oxygen, it is necessary to increase aeration and partially replace the water. It is better to purchase a separate compressor.

Feed quality and overfeeding

Cheap food does not fully meet the individual needs of a particular breed. Therefore, you should never skimp on food for pets. You should also not overfeed aquarium inhabitants. It is enough to sprinkle as much food as will be eaten in 5 minutes. Otherwise, excess food will rot in the soil and accelerate pollution of the aquatic environment, and the fish will begin to die.

Aggressive neighbors

Small fish will be eaten if placed in the same container with aggressive predators. Intraspecific clashes are also common, for example, in cockerels and some cichlids. Conflicts may also arise based on gender. You need to purchase fish with confidence in their peacefulness and knowing their characteristics well.

Spawning

The discovery of a dead fish during spawning indicates that the aquarist did not take into account the behavior of the fish. Some species, such as gouramis and cichlids, carefully guard their offspring, showing hostility towards other inhabitants. Sometimes you will need a spawning aquarium, where the female, male and offspring are placed. However, often the parents do not show care, and the eggs can be eaten altogether.

Diseases

Most often, diseases appear with new inhabitants. Even at the acquisition stage, the aquarist should monitor the activity and appearance of the fish; nothing should arouse suspicion. There is no need to immediately add her to other aquarium pets. It is recommended to place new fish in a separate tank for 2-4 weeks. Symptoms appear gradually, so they will not die for no apparent reason. After quarantine, healthy fish are placed in a common container.

We have collected them in a separate article.

If an illness is detected, it is necessary to remove infected individuals, increase aeration and resort to a daily replacement of 10% of the aquarium water. If a disease is identified that causes fish to die, you can carefully use the medicine.

Prevention

In most cases, fish die in an aquarium due to the inattention and careless attitude of the owner. Every day you need to count the number of fish and monitor their interaction, siphon the soil once every 1-2 weeks, and change the water if necessary. The aquarist’s task is to do everything for the full life of the fish and respond in a timely manner to changes occurring in the aquarium.