Why Does My Guppy Have A Bent Spine? Causes and Treatment

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Every guppy enthusiast envisions a tank full of happy, healthy fish swimming around, but wait a minute – is that a guppy with a curved spine? Unfortunately, this is a common phenomenon in guppies, and can potentially be a problem for your aquarium inhabitants. On the other hand, some guppies lead perfectly normal lives despite their condition.

So, why do guppies have bent spines? How do you care for a fish with this condition? Read on to learn more about bent spines in guppies and what it means for the health of your tank. We’ll discuss some common causes, means of prevention, and how to provide a good quality of life for all your guppies, regardless of their shape.

Causes of Bent Spines in Guppies

There are a few potential causes of bent spines in guppies, some of which can be managed by the aquarium keeper and others that are simply part of their natural life cycle. Here are some of the most common causes:


Tropical fish, such as guppies, can develop a bent or curved spine due to a condition called scoliosis. Scoliosis in guppies is caused by an imbalance of the muscles that run along each side of the fish’s spine, which results in one side becoming more developed than the other. This can cause the spine to curve at unnatural angles and create an S-shaped or curved spine.

The vast majority of guppy fish with scoliosis have it due to poor genetics, with the malformation being passed on from one generation to another. It is also possible for environmental factors such as poor water quality, lack of nutrition and stress to contribute to the development of scoliosis in guppies. Though rare, injuries to the spine of a guppy can also cause scoliosis.

Scoliosis fish
Image Source: commons.wikimedia.org

Unfortunately, there is no known cure for fish scoliosis. The good news, however, is that it does not usually affect the quality of life for a guppy. Unlike most sick guppies, guppies with scoliosis can still swim, eat, and interact normally. Of course, you should monitor your guppy closely to ensure its condition isn’t deteriorating.

Fish Tuberculosis

Tuberculosis in fish, also known as fish TB, is a rare but often serious illness that can cause a bent spine in guppies. One of the key challenges of diagnosing fish TB is that the symptoms can be attributed to a number of other guppy fish diseases. Symptoms of fish TB in guppies can include scanty scales, loss of appetite, weight loss, hiding, and of course, a curved spine.

As we’ve mentioned, these symptoms are all somewhat general. The loss of scales in particular, can even be misdiagnosed as a simple external injury. It is only when mycobacteria are found in a sample of the guppy’s scales that the diagnosis is confirmed. Unless fish TB is caught early on, its symptoms can become quite severe and even cause death.

Thankfully, most cases of TB in guppies can be treated with antibiotics. Treatment is usually done by adding the antibiotic to the tank, although in some cases, it may need to be administered directly into the guppy’s skin or gills. Alongside treatment, it is important to provide your guppy with a clean and stress-free environment, as this will give it the best chance of recovery.

Genetic Factors

As much as we all wish it weren’t true, genetics can also play a major role in developing a bent spine in guppies. Genes that code for skeletal deformities, such as scoliosis, can be passed on from generation to generation. This means that if a guppy is born with scoliosis or any spine deformity, its offspring are likely to be affected as well.


Given genetics’ importance, taking precautionary steps when buying guppies is important. Pet stores, for example, may stock guppies from unknown origins and with unknown health issues. At the fry stage, guppies may not show any signs of sickness, but their spine deformities may become more pronounced as they grow older.

Fortunately, many reputable breeders are aware of this issue and take measures to ensure that their guppies are healthy and free of genetic defects. They achieve this by making sure that their breeding stock consists only of healthy fish. Good husbandry is vital to any successful guppy breeding program, so please get your guppies from a trusted source!

Swim Bladder Disease

Sometimes, a crooked spine may indicate that your guppy is suffering from swim bladder disease. This is a prevalent ailment, particularly among fish that suffer from digestive issues due to a poor diet. Guppies need a variety of food and high-quality flakes to maintain a healthy digestive system, so be sure to provide your fish with a balanced diet that meets their needs.

Fish flakes may serve as your guppy’s main source of nutrition, but they should not be the only food in its diet. You should also add occasional treats and live foods such as brine shrimp and freeze-dried blood worms for an added protein boost. Spirulina tablets and algae wafers are also a good idea as they are high in essential vitamins and minerals.

Swim bladder disease can be treated with a combination of aquarium salt and the right medication. However, the best approach to treatment is prevention, so be sure to stick with a healthy diet and clean water for your guppy. If you follow these steps, the chances of your guppy developing swim bladder disease will be greatly reduced.

Poor Water Quality

dirty aquarium

Because guppies are such prolific breeders, they are often stuffed into overcrowded aquariums prone to water fouling. Things like fish waste and uneaten food contribute to the rapid accumulation of ammonia in the tank. This toxic substance can quickly cause your guppy to fall ill and develop a curved spine as a symptom or side effect.

To prevent this from happening, you must make sure to maintain optimal conditions in your guppy tank. Keep your fish tank clean by performing regular water changes, and consider investing in a good filter to help keep the water clean and clear. All well-kept aquariums should also be properly ventilated. Oxygen levels should be kept high, and the water should be consistently circulating.

Keeping the water temperature stable is also important for the health of your guppy. As fish that hail from the rivers of South America, guppies tend to prefer warm water between 75-80°F. Cold water can cause stress and reduce your fish’s immune system, making it more susceptible to diseases that can cause a bent spine.

By keeping the water quality of your guppy tank in check, you can make sure that your fish stay healthy and disease-free. Doing so will help reduce the risk of your guppy developing a curved spine or any other deformity.

Can Curved Spines Be Treated?

If your guppy has already developed a curved spine, you may wonder if there is anything that can be done to treat it. The question of whether or not a curved spine can be reversed is a bit complicated, as it depends on the underlying cause.

In some cases, aquarium fish develop a bent spine as a temporary symptom of a disease. Swim bladder disorder, for instance, can cause your guppy to swim awkwardly with an arched back. However, if the underlying problem is addressed properly and promptly, the bent spine can often be reversed.

On the other hand, some fish may suffer from a curved spine due to genetic deformities or other causes. In such cases, there is no real cure for the bent spine, and it cannot be reversed. However, most guppy fish with a permanently bent spine go on to lead a normal life, and the deformity should not be a cause for concern.

The yardstick for determining the best course of action is to monitor your guppy’s behavior. If it appears to be swimming and acting normally despite its curved spine, then it is likely doing just fine, and no treatment is required. If you notice that your guppy’s behavior seems off or appears in distress, you may want to consult a veterinarian to get proper advice on how to proceed.

Should You Euthanize Your Fish?

Euthanasia is a tricky topic, and one that many fish keepers struggle with. Generally speaking, if your fish appears to be happy and content, then it is best to let it be. However, if you think that the curved spine has a significant impact on your guppy’s quality of life, then you can consider euthanasia as a last resort.

If you’ve decided that euthanasia is the best option for your fish, it is important to make sure that you do it humanely. We recommend using clove oil, which is a painless and peaceful way to end the life of your fish. Here’s a quick guide on how to use clove oil for euthanizing fish:

  1. Prepare a separate container filled with water and a few drops of clove oil. Contrary to popular belief, clove oil does not cause any pain or discomfort to the fish.
  2. Place your guppy in the container with the clove oil. Give it a few minutes to become accustomed to the new environment before adding any more clove oil.
  3. Gradually add more clove oil to the container until the fish is completely sedated. This should take about 15 minutes.
  4. Once the guppy is completely sedated, it will become motionless and its gills will stop moving. This indicates that it has passed away. At this point, you can dispose of the dead fish responsibly.

Euthanizing your guppy can be a difficult decision, but it is important to consider its quality of life if it has a curved spine. Ultimately, the decision should be yours and yours alone to make.

The Takeaway

Guppies can develop curved spines for a variety of reasons, including genetic deformities, poor water quality, and diseases. In some cases, this deformity can be reversed by treating the underlying cause. However, in other cases, the curved spine will be permanent. Depending on whether or not your guppy’s quality of life is affected, euthanasia may be a consideration.

We hope that this article has been helpful in understanding why guppies have bent spines and what you can do about it. Remember that it’s always best to consult a veterinarian if you’re ever in doubt. These trained professionals can provide you with the best advice and guidance on how to ensure your guppy stays happy and healthy. Thanks for reading, and good luck!

Wanda is a second-generation aquarist from the sunny tropics of Malaysia. She has been helping her father with his freshwater tanks since she was a toddler, and has fallen in love with the hobby ever since. A perpetual nomad, Wanda does her best to integrate fish-keeping with her lifestyle, and has taken care of fish in three different continents. She loves how it provides a nice break from the hustle and bustle of life.

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