Why Do Goldfish Seem To Die After A Month? (Main Reasons)

Goldfish, just like any other fish, also require a proper aquarium set up with all the needed filters, oxygen, and of course, food. Some people who purchase their first goldfish may think that just by providing them some fish flake and putting them in a fishbowl is enough for them to thrive, but this is a wrong notion. 

Main Reasons Why Goldfish Die Quickly

Stress during the travel.

Your goldfish may be hardy, but rough travel can cause it to exhaust as well. It is also stressful for any fish to experience a bumpy ride while inside a plastic bag.

There is only so much oxygen in there to keep them alive for some time, but if it will take longer for them to be transferred to a suitable aquarium set up, they can get weak in the process. Some goldfish even die within 24 hours due to stress during shipment. 

Remember that the smaller the fish, the more it can get stressed and die from trauma. 

Wrong Aquarium Set Up

You should research what preference your goldfish need for them to thrive. It is also not ideal for you to place your newly bought goldfish inside an aquarium that has no healthy bacteria on it. You should introduce bacteria that will keep the water safe for your fish before buying your fish. This is also called aquarium cycling, and this is required if you want your fish to live longer and not die in just a month. 

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An Aquarium That Is Too Small

If you bought a dozen of goldfish and your aquarium is just good to accommodate five fish or so, then don’t expect your goldfish to live long enough to enjoy their tank. Good bacteria can only break down waste, and if there are too many fishes in the tank, this will cause not enough good bacteria to keep the water environment healthy.

More fish equals more waste, so the water can turn toxic and can kill some of your fish, if not all. 

They Are Not Healthy When You Brought Them Home

Some sellers may not be breeding the goldfish the right way, and they are not giving them a healthy life. When you bought your goldfish, the fish may survive a week.

Other fishes may even have diseases or already dying and may not live long enough for a month. 


A beginner may feed their goldfish, not thinking that it is too much. They may overfeed their fish without knowing it.

Some leftover fish food is not good, not just for your fish, but it can make the water dangerous as the waste can increase the ammonia content in the water.

The more food you give to your goldfish, the more they will excrete waste into the water. This can foul the water fast, which can make the environment toxic for your fish and soon may kill them. 

You should feed them the right amount and ensure that you are giving them the right food. 

Poor Tank Cleaning And Maintenance

It is fitting to clean your aquarium once a week or every two weeks. Water change is important to keep a healthy environment for your goldfish. Removing a percentage of gunk in the water is ideal, and you should replace it with fresh water. Removing the substrate and other dirt inside the tank is crucial to maintaining your aquarium. 

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Some harmful waste products such as ammonia and nitrite can be toxic to your goldfish and can kill your fish in a few days or weeks. 

You may not also know it since you can’t smell ammonia, and the only way to find out the level of ammonia in the water is to test it. 

By cleaning and maintaining the aquarium, you are also making sure that your goldfish will live long and will be happy. 

Incorrect Water Temperature

Changes in water temperature can swiftly kill your goldfish. You cannot just remove your goldfish to clean the tank and make a complete water change without acclimating your fish.

Make sure your goldfish will have a pleasant water temperature and make a slow and steady water change so your goldfish will not die of temperature shock. 

Your Goldfish May Already Have a Disease or is Already Sick

Your fish may already have a compromised immune system and may not fight off any diseases it may have. They may already have a parasite that you are not aware of, especially if you are just a beginner who doesn’t have much knowledge about handling fishes. 

Some stressed fish and those that already have a disease may not live long if you don’t immediately notice their frailty.

Other harmful bacteria may already thrive in your fish and are causing internal and external infection. Some common ailments that you can see in your fish include ulcer disease, plus mouth and fin rot. 

While there is also a parasitic infection that leads your fish to die suddenly. Some samples are lice or ich. 

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You can save them if you immediately notice anything or suspect that something is amiss and get the advice or help of the vet right away. 

Not enough oxygen in the tank can be a reason. Your goldfish can die because of a lack of oxygen in the tank. You may find it gasping for air or struggling to breathe. Ensure that the oxygen in the tank is enough for the number of goldfish that you have. 

Do you have Incompatible fishes in the tank? Some fishes can live peacefully with each other inside the tank, while other fishes can be aggressive and hostile with each other, especially to newly added fish in the tank.

Make sure you are mixing your goldfish with the right fish, so you will see it live longer than a month. When a fish is stressed out with its surrounding, its immune can weaken, and it will not feed as much. It can also get sick after some time when it is no longer feeding and getting along with other fishes.