Guppy Fish Bent Spine – Causes and Treatments

If you’re a guppy lover, you need to know that caring for your fish involves a variety of aspects. These include ensuring quality food regularly, cleaning the water, and preventing microbial and fungi accumulation on the tank’s walls.

Sometimes, however, things can go south despite all your best efforts. Your guppies can sometimes develop life-threatening conditions that could prove deadly without proper assistance.

This brings us to the bent spine syndrome resulting from two potential disorders – scoliosis or tuberculosis.

In this article, we will assess both these conditions to help you identify them sooner and prevent further complications along the way.


Unlike other disorders, scoliosis is only preventable in part. That’s because, in many cases, its triggers are genetic. This means that the fish will develop the condition either at birth or during the fry stage.

It’s easy to tell when your guppy has developed scoliosis due to the specific curvature of the spine. The spine will either form an S or a C and will affect the fish’s ability to swim and move around the tank.

Another key aspect to remember is that adults with scoliosis can reproduce successfully, passing the disorder onto their offspring. Studies show that 90% of the fry will develop the condition if the female guppy also had it. In short, scoliosis will affect the guppy’s quality of life.

It’s also worthy of mentioning that sick fish rarely survive in the same tank with healthy individuals. That’s because healthy fish tend to attack and bully the weaker or sick ones. It’s nature’s way of keeping the population strong and healthy.

I would recommend removing sick fish from the general tank as soon as you spot them to prevent them from reproducing.

This disorder has three main triggering factors:

  1. Inbreeding – This phenomenon generally occurs in smaller fish populations, where the breeder cannot provide new blood to diversify the gene pool. This normally happens when the fish owner only has several fish that will reproduce. The owner will then reintroduce the resulting fry into the main tank, where they will mature and reproduce between them, resulting in inbreeding. Inbreeding has a higher chance of causing scoliosis and you can easily avoid this problem by diversifying the gene pool once in a while. Or simply avoid placing the resulting fry in the same tank with their parents.
  2. Improper Diet and Poor Habitat Conditions – Most novice fish owners have problems figuring out the ideal feeding patterns for their guppies. Guppies are omnivores, which means they need a variety of food sources, including spirulina tablets, brine shrimp, blood worms, veggie pellets, etc. Depriving your fish from the necessary nutrients will increase the risk of scoliosis. The same goes for keeping your fish in overcrowded aquariums and overfeed them, leading to reduced water quality and critically low oxygen levels.
  3. Genetic Factors – This one is pretty much self-explanatory. Like I’ve already mentioned, the vast majority of the offspring coming from a sick female will develop the condition. Left unchecked, these will then grow into sexually mature individuals, reproduce, and create a new pool of sick individuals. You can prevent this by removing sick guppies as soon as you spot them to keep your guppy population healthy and thriving.

When it comes to prevention, things are fairly simply from where I stand. You can easily spot the scoliosis-hit guppies by their curbed spine and erratic swimming pattern. The best you can do is diagnose the condition early and remove the sick individuals from the tank.

Other preventive factors include providing the guppies with a varied food source, controlling the guppy population to prevent overcrowding, and cleaning the tank regularly. Keeping the water in peak condition is necessary to prevent a variety of health issues and improve your guppies’ quality of life.


Tuberculosis is vastly more dangerous than scoliosis for one simple fact – it is contagious. This disease can transmit between other fish, fish to other animals, and fish to humans. You can see why dealing with this condition is not the ideal scenario.

The disease is the result of the Mycobacterium Marinum bacteria, which tends to thrive in dirty waters. This brings us to the main triggering factors of the disease, which include:

  • Lack of maintenance – Unclean tanks will lead to the accumulation of ammonia which is deadly to fish. But that’s not the only problem. Another issue is accumulated waste from rotten food and fish waste, which will create a breeding ground for bacteria. You can easily prevent this problem by maintaining the tank in optimal condition, which includes cleaning it regularly.
  • Poor water quality – It goes without saying that unclean waters will harbor a variety of pathogens, one of them being the Mycobacterium Marinum. Not only that, but dirty waters will also lead to a dangerous accumulation of ammonia and have lower oxygen concentrations. All these issues can come with potentially fatal consequences for your guppies.
  • Overcrowding – Having too many fish in one tank will create a variety of problems. Some of them include cannibalism, as well as the rapid accumulation of fish droppings and dirt. This will make cleaning the tank that much more difficult and lead to a dangerous accumulation of bacteria. Not only that but having much fish in the tank will allow the tuberculosis bacteria to transmit rapidly among the population. The result will be a tank full of dead fish. You can easily avoid that by avoiding overcrowding.
  • Overfeeding – Too much food will affect your guppies’ overall health in time, but that’s not the only problem. An even more serious issue comes from the unconsumed food that will accumulate on the tank’s bed. The food residues will rot away and create a haven for harmful microorganisms like the Mycobacterium Marinum.
  • Sick fish being added to the bunch – This is a common mistake that many fish owners will make. They will purchase their guppies from standard fish shops without assessing their health properly. This can result in a sudden tuberculosis outbreak when unverified, sick fish are introduced into the aquarium holding the healthy ones. To avoid that, I suggest verifying the fishes’ health before acquiring them.

Some of the symptoms of fish tuberculosis, aside from the bent spine, include folded fins, discoloration of the body, loss of appetite, loss of scales, etc.

Now that you know the two main disorders related to bent spine syndrome, the next question is – How do you treat these conditions?

The answer is more straightforward than you might expect – you don’t. Sure, some quasi-treatments are available like antibiotics (Kanamycin, Isoniazid, Neomycin), aquarium salt, or increasing the tank water’s temperature. However, these methods are generally unreliable and can even hurt your fish in the process.

I would advise removing the sick fish from the tank to protect the healthy ones. This seems like the most reliable method of coping with these conditions and prevent the spread effectively.

How to Euthanize Your Guppies?

Now that you’re past the diagnosis phase, the next in line is the treatment. As I’ve already mentioned, the most reliable containment method is removing the sick fish from the tank and, of course, euthanizing them.

But how exactly do you euthanize your guppies? This may seem like a straightforward concept; after all, how hard could it be to kill some fish?

The problem here is not the killing in and of itself but doing it humanely. That being said, you should not:

  • Flush your fish down the toilet – This is the most commonly-used fish-killing method and the most ineffective at the same time. Your guppies will take a long time to die, and some won’t die at all. Not a good option.
  • Let them suffocate – Removing the fish from the water and letting them suffocate will, again, take a lot of time. Considering the suffering that the fish will endure in the process, this method is far from humane.
  • Alcohol baths – Many people throw the fish into an alcohol bath which, yes, will kill it, but at what cost. The alcohol will burn the fish’s gills, causing tremendous suffering in the process.
  • Boiling water – Placing the fish into boiling water isn’t an easy or painless way to go either.

When it comes to euthanizing your fish humanely, using clove oil is the best thing you can get. Clove oil acts as a sedative and causes hypoxia which is pretty much asphyxiation. Death will occur in approximately 10 minutes. While it may sound like a long time, don’t worry, your fish won’t feel a thing since it will be unconscious.

To use clove oil effectively, I recommend mixing the recommended dose in some warm water which you will then pour into the tank with the sick fish. Don’t mix the oil directly into the tank since it will most likely float on the surface.

If your fish doesn’t die in 10 minutes, it probably means that the concentration of clove oil is too low. Add a few more drops into the tank, the bucket, or wherever the euthanasia takes place. That should do the job.


The good news is that both scoliosis and tuberculosis are preventable. To minimize the risk of your guppies catching any of these conditions, you need to:

Maintain the tank water clean, fresh, and oxygenated

  • Clean the tank regularly
  • Don’t overfeed the guppies
  • Don’t overcrowd the guppies
  • Avoid introducing sick fish into the tank

I hope that this comprehensive article has given you the essential tool to prevent and deal with these conditions – knowledge.

avatar Noah
I’m Noah, chief editor at VIVO Pets and the proud owner of a playful, energetic husky (Max). I’ve been a volunteer at Rex Animal Rescue for over 2 years. I love learning and writing about different animals that can be kept as pets. read more...

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