Why do freshwater fish die in the aquarium? 8 Reason here!!

If you like to fish, you must have an aquarium and if that is the case, it is likely that you have already gone through the bad time of seeing one of your fish die. Well then, do not worry anymore, because we help you understand why fish die and what you should do to minimize the chances of this happening again.

A healthy, colorful and full of life aquarium is all you need at home to relax and feel some peace from time to time. So the best thing you can do to thank your pets for this benefit is to take care of them properly. Taking good care of your fish involves much more than watching your diet; a clean environment, water control, temperature, light inputs, and other aspects are basic for the proper maintenance of an aquarium.

If you want to know in detail what are the main causes of fish death in aquariums and what you should do to improve the quality of life of your favorite swimmers, read on and discover why aquarium fish die.

Here we present 8 reasons to fish die in the aquarium

Stressed and sick fish

Fish are very sensitive animals and one of the most common causes of death within aquariums is due to diseases, caused among other things, by the stress they suffer.

Sick fish

When you go to acquire your pets a specialized store, you must be very attentive to the most common symptoms that warn you that a fish is stressed or sick.

freshwater fish die

The visible characteristics of diseases that you should look for are:

  • White spots on the skin
  • Chopped fins
  • Dirty aquarium
  • Little movement
  • Fish swimming sideways
  • Fish floating head

If any of the fish you want to buy has any of these characteristics, we recommend you do not get them. Even if not all fish show these symptoms, if they share the fish tank with sick congeners, it is most likely that they are all infected.

The autochoque of fish

Another important aspect that you must take into account so that your fish do not get stressed and sick, is the transfer of the store to the home aquarium. Later we will talk about the water issue, but regarding the transfer, we recommend you go directly home after buying the fish and of course, avoid shaking the bag with the animals inside.

Another reason that generates a lot of stress in fish is the conglomeration of individuals. When there is much fish concentrated in small dimensions, it can be the case that they hit each other, hurting themselves and considerably increasing their level of stress.

Your fish tank may be large enough, but be careful when cleaning and changing the water, because it is at this time when the fish usually gather in cubes or the space of your aquarium is reduced by the loss of water. Avoid that this situation is too long, since these clashes between fish and the stress that this entails our pets, may favor the emergence of other diseases.

Sensitive animals

Beautiful but very delicate. Avoid at all costs that your fish suffer episodes of stress, this way you will prevent the appearance of other diseases and more importantly, their premature death.

If you have visited the aquarium of your city you have surely seen the warning notices that say “do not hit the glass” and “do not take photos with flash”, because we recommend applying these same gifts to the aquarium of your home.

We have said, fish are very sensitive and scary animals, so hitting the glass of your fish tank constantly is not good for your health, remember that the more stress you suffer, the more likely you are to develop diseases and die. As for the flashes, we apply the same rule: avoid scaring your fish. As long as their quality of life is optimal, their hope of survival will increase.

Water: The world of fish

Another cause of fish die in the aquarium is directly related to their livelihood: water. The incorrect treatment of water, both in terms of temperature, cleanliness. And adaptation, can be fatal for our pets, so check this section on what you have to know to manage the water in your tank.

Control of ammonia and oxygen

fish die

Two very important factors in the life of our fish, oxygen is life, and although ammonia is not death, it is very close to it. Ammonia poisoning and drowning due to lack of oxygen are two of the most common causes of aquarium fish death.

To keep your fish from drowning, keep in mind that the amount of oxygen that may have dissolved in the water of an aquarium is limited. Check well the amount and size of fish you can have according to the size of your aquarium.

The excrement of the fish, the decomposition of the food and the same death of living beings inside the aquarium, give off ammonia, so if you do not want your fish to die before normal you should keep the fish tank clean.

To remove the excess of this toxic waste will be enough to make partial changes of water on a regular basis. And have installed a good filter for your aquarium. Which besides providing oxygen is responsible for eliminating all stagnant ammonia.

Clean water … but not so much

Keeping the water in an aquarium is not as simple as it seems. In addition to the help provided by a quality filter, the water in an aquarium needs to be renewed every so often and if we remember that fish are very sensitive animals, this process can be traumatic for them.

fish die

When it comes to renewing the water of an aquarium. In addition to taking into account what we mentioned about not gathering too many fish in small spaces. You must keep at least 40% of that “old” water and complete with new water. Otherwise, the fish would not adapt to the change and die. This old water must have been treated to remove as much ammonia as possible to be able to mix with the new one and thus, renew the liquid medium of your aquarium.

On the other hand, the new water for the aquarium should never be tap water, chlorine and lime concentrated in the water, which for humans is harmless, could kill your fish. Always use drinking water and if possible, try not to contain any type of additives.

Another important aspect is the use of excessively clean materials. Try that the cubes where you will throw the water or the same fish, have a little of that old water or at least check that they have absolutely no soap residue or cleaning products. In any case, do not forget that you can never use the same products with which you clean your house to clean your aquarium or the material that is in contact with the fish.

Long live the fish

Despite mastering the arts of fish care, it is possible for one to die occasionally or get sick without warning. Do not worry about this, sometimes the fish die without any apparent cause.

The most important thing is that it takes into account the aspects that we have already mentioned and of course, always use common sense. If you know that fish are sensitive and delicate animals but you treat them abruptly. Maybe you yourself have the answer to the question of why the aquarium fish die.

freshwater fish die

Our latest recommendations are:

  • Handle them gently and delicately when changing the water in the fish tank
  • If you buy new fish, introduce them to us in a violent way in the aquarium
  • If you have visitors or there are small children at home, avoid hitting the glass of your aquarium
  • Do not overdo the amount of food that increases the level of ammonia. And the appearance of bacteria in the water
  • No incompatible fish inside the same aquarium
  • Consult the recommended water, temperature, light level, and oxygen level specifications for the types of fish you wish to have
  • If you are going to decorate your aquarium buy quality objects. And verify that they are suitable for aquariums and do not contain polluting agents

In conclusion

We hope after reading this article, you may try to maintain a healthy aquarium with the environment. And reduce fish die in your aquarium.

This article is merely informative. We do not have the power to prescribe veterinary treatments or make any kind of diagnosis. We invite you to take your pet to the veterinarian in case of any type of condition or discomfort.


Rashed Ahmed regularly contributes to lifestyle magazine online and living ideas to various blogs around the web. When he’s not busy working with the work, you will find him undertaking many of her own lifestyle-related topics and living ideas! He has a lot of dreams. He works hard to fulfill his dreams. He loves to share his ideas, tricks, tips, and information by blogging. He also works at innovative business ideas, a business marketing company that committed to helping businesses with online marketing.

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