When a goldfish is sitting at the bottom of the tank it can be for a variety of reasons. Some reasons include problems with the fish’s health, while others are not related to health at all.
Usually goldfish sit at the bottom of the tank due to not feeling well for some reason. Improper water conditions, parasites, stress, GI problems, and swim bladder problems can all cause a fish to sit at the bottom of the tank.
Occasionally you may see a fish sitting at the bottom of the tank because they are sleeping but all other potential health problems should be ruled out before assuming that sleeping is why your fish is bottom sitting.
Improper water conditions
High ammonia or nitrites can lead to a goldfish sitting at the bottom of the tank.
They will show signs of lethargy, a change in color, and fins that are jagged. It is imperative to check your aquarium water frequently to ensure that these levels do not rise.
You should have neither ammonia or nitrites in a properly maintained aquarium.
If you suspect high ammonia or nitrite then you should test the water to verify. If either of these is a cause, then a large water change is necessary. Frequent and large water changes and testing the water daily to ensure that ammonia or nitrites go away will help the fish feel better and get them back to normal.
Parasites, fungus, or bacteria
Parasites can get into an aquarium due to introducing something new that has parasite eggs on it, such as a new fish that wasn’t quarantined, or a living plant.
Any amount of parasitic load on a fish can cause them to feel unwell and want to bottom sit.
Fish can also be seen scratching on surfaces of the tank because they are trying to itch themselves and if the parasites persist then they will start to bottom sit more often.
Once parasites attack, they will eat the fish’s gills, fins, and body. Once wounds occur then bacteria or fungus can move in and cause an even greater problem. A fish getting a bacterial or fungal infection secondary to a parasite can happen easily.
Treating parasites can be done with a broad-spectrum antibiotic. There are two different groups of parasites. Lice and anchor worms are one group and can be treated with parasite guard. Flukes, worms, and protozoans are the second group and can be treated with a praziquantel based medication.
You should always verify what parasite you are trying to treat for and quarantine the affected fish so other fish in the aquarium don’t get ill from the treatment.
Fish becoming stressed can occur due to improper water conditions, overcrowding, an aggressive fish in the tank, or being transported.
When you transport your fish, either by mail or from a local store, then they can become very stressed and can bottom sit. If you have a new fish and they are acting this way, and you have ruled out health and water conditions, then you can leave the fish alone for a few days in a dim room to allow them time to recover and rest.
If the stress is due to overcrowding, then removing fish or getting a larger tank which will allow more space for the fish to move around is needed. An overcrowded tank will quickly pollute the tank with waste and create poor water conditions which can lead to further health problems.
If you find out that the problem is an aggressive tank mate, then you need to remove the aggressor. If a new tank is not available to house and keep the aggressor, then it will need to be rehomed. An aggressive fish can cause injury to tank mates and cause infections to occur that can harm the other fish.
If there are any problems with the GI tract, such as constipation, this can cause the fish to drop to the bottom of the tank or get unbalanced in the water due to offsetting of the swim bladder.
The swim bladder is what allows the fish to move around in the water due to the little sacs that fill with air and allow them to move around the tank efficiently. When constipation happens then air gets trapped in it and prevents the fish from moving around like they need to. They can get lethargic, not want to eat, and in some extreme cases they may float upside down.
You should stop feeding your goldfish if it is constipated to allow it to try and pass the blockage. You can try and feed peas to help clear out their digestive tract and get it back to normal motility.
Once the constipation is cleared up and the fish is back to acting normal then it is recommended to switch up the diet to a more gut friendly one for the fish and add in some live foods and greens. It is imperative to catch constipation early to be able to keep the fish moving normally.
If your goldfish is sitting at the bottom of the tank, then there are a few reasons this can be occurring. It can be health related or related to the environment they are living in. They can be bottom sitting due to water conditions, parasites or bacteria, stress, or gastrointestinal problems.
If they are bottom sitting due to water conditions, then this needs to be corrected with checking the water daily and doing large water changes until the water is within appropriate parameters.
Parasites can be treated with medication, but it is recommended to verify the parasite, and any accompanying bacteria or fungal growth to ensure that the appropriate treatment is administered.
Stress needs to be corrected with allowing the fish to calm down in a dim room and given a few days to adjust to the new environment.
Gastrointestinal problems need to be treated quickly and appropriately, using peas is helpful to move constipation through. Swim problems can occur due to constipation and other GI issues.
Bottom sitting is a health problem that should be dealt with in a timely manner to ensure the health of the goldfish in the aquarium.