Guppy With A Bent Spine? (Main Causes Explained)

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Last Updated on 2023-12-18

If your guppy has a bent spine, then, unfortunately, the outlook is pretty bleak. In most cases, when a guppy has a bent spine, the chances are they may not survive.

But if you’re curious why it’s happened, then here are the 3 most common causes of a bent spine in guppies!

What Are The Three Main Causes Of A Guppy With A Bent Spine?

The three main things that will cause your guppy to have a bent spine are tuberculosis, scoliosis, and swim bladder disease. Fortunately, if your guppy is suffering from swim bladder disease, you may be able to help them. However, if they’re suffering from the other two, then euthanasia is the best choice.

Here’s a more in-depth look at all three.

Fish Tuberculosis

Fish tuberculosis is caused by bacteria in the tank called Mycobacterium Marinum. Once one guppy is infected with it, it can spread extremely quickly to the other fish in your tank.

As well as noticing a curved spine when your guppy is suffering from fish tuberculosis, you may notice the following symptoms as well:

Loss Of Appetite

When fish are sick, they rarely want to eat. And this is the case with tuberculosis. When your guppy is suffering from fish tuberculosis, one of the biggest tell-tale signs is a huge drop in weight. They will often look emaciated and thin, as well as have a bent spine.


When your betta is sick with tuberculosis, they’re also going to show symptoms of lethargy as well. They’re going to be too sick to move around, and instead, they’re going to want to hide somewhere safe away from the other fish.

Skin Defects

If your guppy is suffering from fish tuberculosis, then you may also notice that they start getting problems with their skin. One of the problems you may notice is a loss of scales. Aside from these, open wounds, discoloration, lesions, and blood spots are all likely to appear.

Protruding Eyes

You may also notice when tuberculosis becomes more severe that your guppy suffers from protruding eyes. This happens because the organs behind the eyes start to swell up, pushing the eyes out.

Fortunately, though, this could also be a symptom of popeye and cloudy eyes, which are much easier to treat!

Can You Cure Fish Tuberculosis?

Unfortunately, once you realize that your guppy is suffering from tuberculosis, the chances of saving them are extremely slim. The moment you start to notice the symptoms, the amount of internal damage that has been done is extremely high.

Often the best course of action is to euthanize your guppy instead. And most importantly, when you do notice that your guppy has fish tuberculosis, you should remove them from the tank immediately, so it doesn’t spread to other fish.

If you do want to try and cure your guppy, you’ll need to use an antibiotic. Medicine such as Kanamycin is your best bet.

Preventing Fish Tuberculosis

Fortunately, you can do a lot to stop your guppy from contracting fish tuberculosis, and it all stems from making sure that their immune system is strong. So make sure you’re keeping the water in the tank clean, you’re feeding them properly, and you’re quarantining any new additions to your tank.


The second cause of a bent spine in guppies (and generally the most common) is scoliosis.

Scoliosis will begin to develop while your guppy fry is still in the larval stages of life. As well as this, female guppies can also suffer from scoliosis after becoming pregnant and giving birth.

If your guppy has scoliosis, it isn’t good. They often have trouble swimming and end up getting harassed by other fish in the tank who see them as weak.

As well as this, it’s also going to affect the growth rate of your fry that are suffering from it as well.

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What Causes Scoliosis?

Because scoliosis can’t be cured, it’s better to figure out what’s causing it and prevent it instead. Unfortunately, some of the causes of scoliosis are often beyond your control, but there are some you prevent!

Here are the causes of scoliosis:

Bad Diet

If you’re not feeding your guppy fry with a good diet, then they’re much more likely to develop scoliosis due to the lack of nutrition. And remember, as well as feeding your guppy fry enough, you should also make sure you’re feeding them high-quality food too.

You should be feeding your guppies a mix of vegetables as well as meat to make sure that they stay as healthy as possible and reduce the chance of scoliosis.

(Find out more about what guppies should eat and the best fish food to feed them!)

Bad Tank Conditions

You should also make sure the water conditions are as close to perfect as possible. Your guppies need enough light and oxygen in their tank; otherwise, they’ll suffer from a whole host of diseases.

To increase the oxygen levels in the tank, consider adding an air bubbler or plants.

Also, make sure that you’re not overstocking the tank. Not only will these cause the tank conditions to drop, but the more fish in the tank, the more oxygen will be consumed as well.

(Find out how many guppies to keep in a 5 gallon, 10 gallon, 20 gallon tank.)


Unfortunately, one of the most common causes of scoliosis in guppies is inbreeding. The smaller the gene pool, the more likely it is that scoliosis as well as a whole range of other deformities, are likely to occur.

While there’s not much you can do to stop this from happening to fry born in your tank; you can reduce the chances by sourcing your guppies from reputable sellers.

(Find out how to selectively breed your guppies.)

It’s Hereditary

As well as this, if your guppy breeds when they have scoliosis, then there’s an extremely strong possibility that their fry will end up with scoliosis as well. Some even estimate that there’s a 90% chance that the fry will also inherit the disease.

If you notice a female guppy who has scoliosis, then it may be worth moving her to a tank away from males so she can’t breed.

However, don’t worry too much if she does. Normally the fish in your tank will eat all of the babies before they have time to reach maturity and suffer from scoliosis.

Swim Bladder Disease

Lastly, a bent spine can also occur in the most severe cases of swim bladder disease. If you notice that your guppy has been sick for a while and then developed a bent spine, then swim bladder disease is the most likely cause.

There are many factors that can cause swim bladder disease, so it can be hard to pinpoint the exact problem that’s making it happen.

However, generally, it’s caused by one of the following:

  • Overfeeding/constipation
  • Shock
  • Parasites
  • Bacterial infection
  • Low water temperature
  • Cysts in the kidney
  • Egg binding

As you can see, there are many different causes, and the treatment for each is going to vary.

Symptoms Of Swim Bladder Disease

If your guppy is suffering from swim bladder disease, then there are plenty of other symptoms that will help you diagnose it, without having to worry that it’s being caused by something else.

Some of the common symptoms include:

Lopsided Swimming

This is the biggest tell-tale sign that your guppy has swim bladder disease. No matter what happens, you’ll notice that their body always ends up at an unnatural angle. They may start floating to the surface of the tank when they don’t want to or sinking to the substrate.

Whatever the case, you’ll notice that their swimming is lopsided. In more severe cases, they may not even be able to stay upright and may swim upside down.

A Distended Belly

When your guppy is suffering from swim bladder disease, a distended belly goes hand in hand with a curved back. And it’s a tell-tale sign that the swim bladder disease has either been caused by constipation or overfeeding.


Now you know all the different causes behind your guppy having a bent spine, you should be able to figure out what’s causing it and, more importantly, what you can do to stop it! However, remember, in most cases, there’s not much you can do to stop it from happening.

If you liked this article, you might also like to know whether guppies lay eggs and about other problems such as columnaris, dropsy, and velvet.

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