Why Do My Goldfish Keep Dying? (And What To Do)

If you are new to owning fish, you may have thought that owning this particular pet may be pretty simple. However, just like any other pet, fish are complex and need a variety of things to ensure that they live their lives to their fullest potential and have a long, happy life!

You may have encountered some problems, the saddest of all being why do my Goldfish keep dying? Well, here we have accumulated a number of things you may not be doing and advice on how to best look after this pet!

Why Do My Goldfish Keep Dying?

Here are all the reasons that your Goldfish could be dying, the symptoms that they exhibit, and, more importantly, what you can do about it!


Goldfish are peaceful fish that will swim the range of their tanks. You will get to know your Goldfish and how they act, so you should notice if there are any changes in their behaviors.

If your Goldfish present any of the following symptoms, then something could be wrong, and the answer to why do my Goldfish keep dying!

  • White spots on their fins
  • Not eating their food
  • Swimming upside down or seeming disorientated or less movement
  • Continuously going to the surface for air
  • Bloating
  • Erratically energetic
  • Isolated from the other fish
  • Lumps/wounds
  • Torn fins
  • Discolouration
  • Rubbing itself on solid objects

If you have noticed any of these symptoms, then below we have a range of different problems that it could be and how to avoid them!


You may have seen Goldfish in small fish tanks before, as some people think that Goldfish being a cold water fresh fish, are an easy pet. Well, this is completely wrong! For just one Goldfish, we recommend 40 gallons of water for the first one, and then an additional 20 gallons of water for each one added to your tank!

Goldfish thrive in vast amounts of water; however, this is not possible for a personal aquarium. It is important to give them as much room as possible; otherwise, they will become stressed, which can lead to them becoming lethargic, not eating, and then dying!

Not having enough room for a young fish can mean their growth is stunted, which can cause some deformities! Not only is stunted growth an issue, but the temperature will rise with more fish in the same tank while also having to live in their own waste in a smaller area.

Please take into account how much you can accommodate for your fish before having them, or you will continuously have the same issues with them dying.

Other Fish

Goldfish are very peaceful fish! They are in the same family as Koi fish and, in Chinese culture, are said to be lucky and bring good fortune!

With this in mind, it’s important to match your fish’s temperaments to those that share a community tank! Goldfish can get bullied by other fish with aggressive temperaments as they try to assert their dominance. They won’t think twice about taking chunks out of your Goldfish!

This problem brings the risk of dying from wounds whilst also increasing their stress levels in abundance.


To negate this issue, keep Goldfish with fellow peaceful fish to ensure they are happy! The less stress the Goldfish have, the longer they live!

With that being said, Goldfish also like the company of other Goldfish. Another problem you may face is that your Goldfish may get lonely and bored by itself! We definitely recommend acquiring your pets in pairs!

(You could also try other tank mates like shrimp, minnows, glofish, and guppies.)

Water Quality

One of the key causes of why your Goldfish may be dying! Water quality is fundamental when owning fish! Just like our environments will really affect us!

Bad water quality can cause problems for your fish, such as harmful bacteria, lack of oxygen, not wanting to eat, and risks of infection.


The first thing we need to do to ensure water quality is to do regular tank checks! We want to remember to reduce the chances of food build-up in the tank, just as we explained before.

Another way of ensuring water quality is checking the pH levels are correct! The most suitable pH levels for Goldfish range from 7.2 to 7.8. This level needs to be consistent too. Any sudden changes to the pH levels could result in disaster, which we will go into later.

Just like pH level, the temperature of the water is really important too. Goldfish are freshwater fish, so they thrive in temperatures between 20 – 23 degrees celsius. Any colder and your Goldfish will become lethargic, which may lead to them not eating and dying. They cannot regulate their own body temperatures so rely on you to do it for them!

Alternatively, making the water too hot, and the Goldfish may become over energetic, which is a major cause for concern as there is a lack of oxygen with warmer temperatures. This can then lead to suffocation, so again, consistently check the temperature and ensure there are no sudden changes!

Goldfish are dirty fish, which all comes down to the amount of waste they produce! Therefore, we want to keep a consistently clean tank. That means we do a 20% water change every 7-10 days and ensure the water is treated! By leaving a tank dirty, it promotes bacterial growth and parasites, which is deadly for your Goldfish!

Another aspect that is fundamental to your Goldfish tank will be a filtration system; as previously stated, a Goldfish bowl is not sufficient. When buying a tank from an aquatic expert, ask them for the best filtration system to ensure the water stays as clean as possible to reduce the risk of poisoning your Goldfish with bad toxins.


Goldfish are notorious for eating anything that will fit in their mouths! This is a problem for your small fish, the amount of waste they produce, and the general cleanliness of their tanks!

The other concern which can lead to their death is the type of substrate you are using in your tank that could cause blockages! Obviously, the more the fish grows, the more their mouths grow!


To avoid any hazards of choking, it’s important that you get the right size substrate. We need the substrate to either be a sandy texture, so it’s too small for them to choke on, or for rocks that are bigger than their mouths!

You will need to judge this from when you first get your Goldfish and measure it alongside their own growth! The last thing we want is for your new pets to choke on something that could easily be rectified!

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Overfeeding is a real problem for fish. Not only do you risk their health from weight gain, but the uneaten food can cause major problems.

Uneaten food left in the tank will rot, which isn’t a nice environment for anybody! This will have effects on the water quality of the tank, which we know is detrimental to Goldfish! Uneaten food causes a build-up of ammonia, which is a very toxic gas, especially to your Goldfish.

The effects of ammonia on your Goldfish include discoloration, lesions, and remaining at the surface for air.

(Find out more about ammonia poisoning.)


To ensure you don’t risk your Goldfish, use the method of only feeding it what it eats within 5 minutes to start with. If you have any food remaining, you know you should be feeding your Goldfish less. Additionally, clean out any spoiled or uneaten food to keep your tank clean.

Parasites And Disease

We now know all the causes that can create a bad environment for your Goldfish, but one common parasite that may affect your Goldfish is parasitic worms. Not only this but they can also be affected by parasite flukes and trichodina if you are keeping Goldfish in a pond. An extremely common disease that may affect most fish is Ich or ‘the white spot disease.’


Now, if your Goldfish has parasitic lice, they will be seen to be rubbing themselves on coarse areas of the tank, such as the glass of rocks. Your Goldfish will be incredibly itchy; this will then create injuries to your fish that can kill them.

To treat the parasitic lice, you will want to use an insecticide for your tank, which will enable the lice to drop off the fish within two hours. It’s important to remember that you won’t be able to see the lice!

To prevent any infestation of lice, ensure that you quarantine new fish from your tank for around 2 weeks to ensure they are okay. You also want to make sure that the temperature and pH level are constantly at the recommended levels to ensure no growth of bacteria.

To prevent Gill and skin flukes, again, keep your tank clean! This parasite will increase damage with a dirty, warm tank, so it’s especially important to not overstock your tank and do regular checks!

Trichodia prevention is the same as the previous techniques; water quality is key in keeping your Goldfish safe, as well as not overstocking your tank!

Ich is a disease that most fish may come across; it can be spread by fish and be transferred to different tanks, so you need to ensure that your fish are healthy when buying them! Just like with lice, it will be best to quarantine your fish at first, to lower the risk of contamination to the rest of your tank. Doing regular checks and keeping stress levels down will help.


Similar to the parasites, Goldfish are also susceptible to infections. Infections can happen from exposure to parasites, but also from any damage they may have had in their tank.


It’s imperative that you follow the advice stated above. Overstocking your tank can raise temperatures, which can create bacteria, as well as a lack of oxygen, so don’t do it!

Ensure that your Goldfish is happy and eating, as a lack of food can cause susceptibility to infection, just as it would with us!

Make sure you are not putting any aggressive fish in the tank that will bully your Goldfish and harm it. Any lesions created on the skin create bacteria that would be detrimental to your Goldfish.

We can’t reiterate enough, check your water quality often and do partial water changes! This is the most important thing to do to provide safety for your pets!

Why Do Goldfish Die Suddenly?


As with the other symptoms we have listed, shock can also present the following symptoms.

  • Swimming erratically around the tank
  • Swimming to the surface appearing to gasp for air
  • Appearing confused, disoriented or swimming upside down
  • Attempting to get out of the tank
  • Bumping into the glass or objects in the tank

Again, you know how your Goldfish behaves or is supposed to and what appears to be out of the ordinary. Factors such as bad water quality exposure to a sudden change in pH level or temperature will also put your fish into shock.


As we have messaged thoroughly before, do checks on your fish! We recommend doing water checks, along with temperature and pH level checks, whilst feeding your fish every day.

This is to ensure that if any changes do take place, they can be rectified immediately.

However, when changing your water, ensure that it’s at the same levels that your fish is accustomed to; when fish go into shock and die, it’s because they have been exposed to a drastic shock that their body cannot acclimate to.


Contaminants are the running theme of this article. We now know that contaminates are detrimental to our Goldfish’s health.

In some cases, our Goldfish may be able to survive through brief exposure to certain situations; however, it would be best not to risk it!

To recap, we want:

  • Good water quality – by doing tank checks
  • Consistent temperatures and pH level
  • Agreeable temperaments in a community tank
  • Not overfeeding as this can cause rotting food left in a tank
  • To quarantine any new fish that are being placed in the tank

These factors may cause your fish to die. With some of them, it may be a slower process that happens over a few days to weeks that you may not be aware of if you aren’t doing the proper checks. We also don’t know how each fish is going to react to certain things.

In some cases, some fish may be able to deal with short exposures to things, whereas others may die suddenly. It all comes down to prevention, rather than taking any chances on your Goldfish’s lives!

So, in conclusion, there are many reasons that your Goldfish may keep dying. Their habitat is so important to take care of with regards to their quality of life. Ensuring you monitor all these things will enable you to have happy fish that live their expected long lives!