goldfish dead at bottom of tank

Goldfish dead at bottom of tank

In order to prevent the death of fish in fish tank, it is important to adhere to the rules for their care and maintenance, to be able to monitor their condition, and most importantly, to know the main reasons why they may die.

Why, for no apparent reason, do the fish at home in the aquarium die, what does this happen, and what to do about it? Why goldfish dead at bottom of tank? The article will provide all the necessary information on this issue.

Goldfish die one after another – what is the reason?

There are many reasons for the death of goldfish at bottom of tank. In an unnatural habitat, fishkeeping can be difficult.

Therefore, the basic rule of their maintenance is that the conditions in the aquarium should be as close as possible to the natural environment characteristic of each individual species of fish.

The owner needs to be attentive and, at the slightest signs of malaise (poor appetite, lack of activity), try to find out the reason in order to prevent the death of the pets.

Knowing the main ones will help eliminate possible mistakes in the maintenance of these underwater inhabitants. Let us examine the most common causes of the death of fish in more detail.

Goldfish are dying from nitrogen poisoning

This reason is fairly common. Nitrogen compounds are formed as a result of the vital activity of fish and other inhabitants of the aquarium.

Also, the appearance of harmful compounds and water pollution in the aquarium is facilitated by:

  • presence of uneaten food,
  • non-compliance with the rules for changing the water in the aquarium,
  • the cleaning filters are dirty or improperly used.

A rotten smell and cloudy water are the first signs of poor water quality. In addition, special tests to determine the level of contamination can be purchased at pet stores.

In the case of nitrogen poisoning, the goldfish should be transplanted into a clean container, cleaned the aquarium of contaminants, and replaced with water up to 25% of the total volume.

When moving, you should prepare the water in advance, which should be settled and as close as possible in temperature to the water to which the fish have become accustomed. To speed up the cleaning process, special charcoal can be added to the filter.

Water temperature

Water temperature is another important factor in keeping aquarium fish. It should be neither too low nor too high.

Therefore, during the cold period, it is important to maintain the room temperature using heating devices.

It is also advisable to purchase a special water thermometer with which to take measurements in the morning and evening hours.

Attention is also important for fish in the summer, when the water in the aquarium heats up and the oxygen level in it drops sharply, the underwater inhabitants can suffocate. The optimum temperature for an aquarium is 25 degrees.

In no case should a sharp temperature drop be allowed. This negatively affects the health of underwater inhabitants and can lead to death.

H2O composition

The water in the aquarium must comply with all acceptable standards, otherwise, the fish simply cannot live in it.

It is desirable that the water is of medium hardness, and the level of acidity in it is neutral. The level of chlorine and other chemicals should also not be violated.

You can bring water indicators back to normal using:

goldfish dead at bottom of tank


When transporting from place to place, it is necessary to take into account the conditions of the former life of underwater inhabitants.

Adaptation should be done gradually:

  1. First of all, the bag with fish should be immersed in the aquarium for around 15 minutes so that they gradually get used to the temperature.
  2. You can then add a small amount of aquarium water to the bag.
  3. After another 15-20 minutes, you can add some aquarium water. In total, add water at least 3 times.
  4. Populate the fish into a new aquarium.

In order for the adaptation process to be successful, in the first few days, you should give your pets maximum attention, make sure that all requirements for their content are met.

Goldfish die with a lack of oxygen

The water in the aquarium must be sufficiently saturated with oxygen, otherwise, its inhabitants may die and you will find your goldfish at bottom of tank.

The most common factors that negatively affect the oxygen saturation of water are:

  • an abundant amount of vegetation,
  • an increase in temperature (especially in the summer heat, when the water in the aquarium overheats),
  • the presence of harmful microorganisms in the water.

If the fish die from a lack of oxygen, aeration should be increased using a special compressor, as well as a partial water replacement.

With a lack of oxygen, the aquascaper may notice that his charges float closer to the surface, trying to swallow air.

Feed quality and overfeeding

Fish food should be chosen taking into account individual preferences and characteristics of the breed, you should not save on such an important component.

Overfeeding is another possible cause of finding your goldfish at bottom if tank. The following rule applies here: feeding should be carried out at the same time, the food should be poured onto the surface of the water in an amount that will be eaten in 5 minutes.

If there is a lot of excess food left in the aquarium, its particles can rot in the soil and cause contamination of the aquatic environment.

Aggressive neighbors

Breed incompatibility can also be fatal. Aggressive predators can simply eat less powerful inhabitants, so when buying different breeds, it is important to know their characteristics and take into account the possibility of their peaceful neighborhood with each other.

Before buying, you can find the necessary information on the Internet, read special literature, and consult with the employees of the pet store.

By the way, on social networks, you can find special compatibility tables for different types of fish.

Spawning period

During spawning, the individual characteristics of some species should be taken into account.

So, for example, gourami and cichlids can show hostility towards other inhabitants, protecting their offspring. Therefore, the family can be moved to a separate aquarium.

There are often cases when, in aquarium conditions, the fish do not want to breed and eat their own eggs.


When buying a new fish for an aquarium, it should first be placed in a separate container for a period of 2-4 weeks in order to identify possible diseases and not infect existing ones.

The fish should be carefully examined and monitored for its activity.

If a disease is detected, infected individuals should be removed and aerated in the aquarium increased. In addition, it will be necessary to replace water with fresh water – no more than 10% of the total volume daily.

Fish medicines are also available in specialized stores.

What to do when you find goldfish dead at bottom of tank?

If a dead fish is found:

  1. Remove the dead body from the aquarium.
  2. Inspect the dead fish: assess the integrity of the scales, fins, tail. The appearance can indicate a possible cause of death – poisoning with contaminated water, illness, aggressive neighbors.
  3. Inspect the other inhabitants of the aquarium to make sure they are free of contamination and are doing well.
  4. Check the water using special drip tests, which will give an accurate indication of the presence of harmful substances in the water.

Based on the test results, it will already be possible to decide what to do next. If the water in the aquarium meets all the requirements, then another reason should be looked for.

Remember that there may be several reasons at once, among them may be the age of the fish and stress due to changes in conditions of detention.


So, having found a dead fish, it is important to find out the reason in order to prevent the death of the rest and in the future to try to follow all the rules of care.

Usually, determining the cause of death is not difficult; this can be done according to the characteristic features given in the article. In a difficult case, you can ask for the help of specialists.