Understanding Guppy Bent Spine: Causes and Solutions

Sharing is caring!

It’s becoming increasingly frequent these days to hear about guppies suffering from congenital health problems, and one of the common complaints is of guppies with bent spines.

Decades of ill-advised breeding have produced guppies that may be beautiful to look at but are often far less robust than their wild ancestors. The genetic problems are compounded when guppies are kept in poor water quality or given a diet that’s lacking in essential vitamins and minerals.

Since prevention is much more effective than treatment in the case of a bent spine, let’s take a look together at the major causes of bent spines in fish and how to minimize its occurrence.

Bent Spine in Pregnant Guppies

Guppies are livebearers, meaning that rather than laying eggs, they give birth to live young. When a female guppy is heavily pregnant, the strain on her body can cause her spine to deform and bend. This is especially noticeable just before and during labor.

Occasionally, a female guppy’s spine can remain permanently bent after giving birth, too. A permanently bent spine in fish and other vertebrates is known as scoliosis.

But while scoliosis is occasionally caused by an especially difficult pregnancy, it appears more often at a young age due to genetic issues.

Scoliosis in Guppies

Scoliosis normally develops in the fry or larval stages of a guppy’s life, but can occasionally appear later, especially during pregnancy in female guppies. It results in a spine with an ‘S’ or ‘C’ shaped spine.

Permanent scoliosis negatively impacts the quality of life in aquarium fish. Guppies with pronounced scoliosis struggle to swim and can easily become the victims of bullying from their tank mates. Symptoms either remain stable or become worse during the fish’s life, but sadly, scientists still haven’t found a cure for scoliosis.

Causes of Scoliosis in Guppies


One of the main causes of scoliosis in guppies is inbreeding. If you’ve ever kept male and female guppies together, you’ll know how much these livebearers love breeding together! So much so that guppies are typically unfussy about who they mate with, and inbreeding within the same guppy family is not uncommon.

When inbreeding occurs, it weakens the genetic integrity of the guppy offspring. Mutations and deformities happen more frequently, and one of the many ailments that inbred guppies can suffer from is scoliosis.

Allowing Fish With Scoliosis to Reproduce

Once scoliosis has shown up in a guppy population, it can easily be passed on to the next generation if fish with the condition are allowed to reproduce.

Since it is a largely hereditary condition, the offspring of guppies suffering from scoliosis are highly prone to developing scoliosis, too.

Poor Diet and Tank Conditions

As well as genetic factors, scoliosis may be brought on or made worse by environmental factors.

Although guppies are remarkably tolerant fish that are often recommended for beginners, they still require a diverse diet and proper tank maintenance to remain healthy.

If baby guppies grow up in a tank that has high levels of fish waste, low dissolved oxygen levels, and a high level of harmful microorganisms, they may be more likely to develop or experience a more acute version of debilitating conditions like scoliosis.

Treating Fish with Scoliosis

As mentioned previously, there is no cure for fish with scoliosis. If symptoms are mild, it may still be possible for your guppies to live a relatively happy life.

If, however, your guppy is struggling to swim or is becoming bullied by other fish, it may be kinder to euthanize your guppy. Obviously, this is not an easy decision, and not to be taken lightly. The truth is that in some situations, it may be kinder to the fish to put a swift end to its misery rather than letting it suffer for years without hope of recovery.

Whether symptoms are mild or severe, it’s important to prevent affected guppies from reproducing. As I’ve pointed out, scoliosis can easily be genetically inherited by the next generation, which would only cause them to repeat the needless suffering as the parent fish.

Guppy Rickets

Another cause of a curved spine in guppies is fish rickets. Rickets is a potential health condition in vertebrates including humans where bones (including the spine) don’t develop the necessary hardness and strength because of a dietary deficiency.

Since a lack of vitamin A, vitamin D or calcium is usually to blame for rickets in fish, the best way to solve the problem is to make sure that young fish get a good supply of both. Ensuring your fish continue to receive a diverse and balanced diet throughout their adult lives will help prevent bone problems such as bending spine syndrome later in life, too.

While high-quality commercial fish foods, such as flake foods, usually contain sufficient vitamin contents to sustain your fish, the vitamin contents are among the first of the nutrients to degrade and become depleted in fish food once the pack has been opened (see my article on fish food expiry).

Good sources of vitamin A are said to be leafy greens and crustaceans, whereas vitamin D is abundant in snails, shrimps, and some types of worms.

Feeding your fish live and frozen foods, as well as dried foods, is the best way to ensure a complete dietary profile that will help your fish develop into and remain healthy, resilient specimens.

Guppy Fish Tuberculosis

guppy bent spine

Another cause of guppies and other fish with a bent spine is ‘fish tuberculosis’, also known as ‘wasting disease’.

What is Fish Tuberculosis?

Fish tuberculosis is a serious bacterial disease in fish caused by Mycobacterium genus bacteria – most notably Mycobacterium marinum. It is called ‘fish tuberculosis’ because it is closely related to human tuberculosis caused by Mycobacterium tuberculosis bacteria.

Common Symptoms of Fish Tuberculosis

Different types of fish tuberculosis can cause different symptoms. Whereas some forms are localized, others will infect the whole system. As well as a bent spine, there are some other classic symptoms of fish tuberculosis to watch out for:

  • Uncoordinated swimming – fish suffering from fish TB may struggle to control their movement or maintain a horizontal position in the water.
  • Abdominal swelling – internal bacterial infections like fish TB can often cause stomach bloating or dropsy. Protruding eyes and loss of scales may follow.
  • Loss of appetite – fish refusing to eat is a classic sign of many diseases, leading to a loss of weight.
  • Discoloration – just as with humans, if your fish turn pale and lose their color It can indicate a health problem.
  • Skin ulceration – Skin lesions and ulcerations are typical symptoms of fish tuberculosis.
  • Folded/clamped fins – Fish clamping their pectoral fins is a common sign of ill health.
  • Internal white nodule formation – the most reliable diagnosis of fish with tuberculosis is an autopsy performed by a qualified veterinarian. Fish suffering from fish TB can reveal white nodules growing on the liver, kidney, and spleen in freshwater and saltwater fish.

Causes of Fish Tuberculosis

There are several ways that fish tuberculosis can enter an aquarium, but it’s important to note that the disease thrives best in poor water quality, when the fish tank hasn’t been cleaned regularly, and your fish’s immune system is already weakened and susceptible to infection.

Introducing an Infected Fish

The most obvious way for fish tuberculosis to enter a new aquarium is with the introduction of a fish that is already infected with the disease. Since fish tuberculosis is highly contagious, a fish suffering from the disease will likely pass it on to all other members of the aquarium, including guppies.

Carried by Aquatic Plants or Aquarium Decor

Secondly, fish tuberculosis can contaminate a tank when live plants or aquarium décor are moved from one infected tank to another. Since Mycobacterium spp. bacteria can survive for long periods without a host, it can lie dormant on the surfaces of plants, rocks, or substrates and wait for a susceptible fish to strike.

Introduced by Dirty Hands

The third way that fish tuberculosis can be transferred to an aquarium is by the dirty hands of the fish keeper.

As Mycobacterium bacteria can be carried on human skin, they can get transferred if you put unclean hands in aquarium water. This is especially likely if you’ve recently had your hands in another tank infected with fish tuberculosis and then put them in a different tank.

How to Prevent Fish Tuberculosis

To prevent fish tuberculosis, we need to address each of the above causes.

Quarantine New Fish

Since diseases like fish tuberculosis can easily be introduced by fish from the pet store, many aquarists prefer to quarantine new fish for 4-6 weeks in a specially dedicated quarantine tank. During this time, you can closely observe your new fish to see if any disease symptoms show up (check the symptoms list above).

If no symptoms are revealed, it’s generally safe to add new fish to the tank. It must be noted, however, that some forms of fish tuberculosis don’t always reveal overt symptoms, meaning there’s no way to guarantee the absence of the disease.

Take Care When Adding Rocks and Plants

Because aquatic plants can also transmit certain pests and diseases like fish tuberculosis, anchor worms, and trumpet snails, some aquarists also prefer to quarantine their plants before introducing them to their main fish tank. If you have fish living in your quarantine tank with new plants, they’ll probably show symptoms of the disease if the plants are infected.

In general, be careful to buy your plants and aquarium décor from reputable sources that take care of their tanks and materials.

Sterilize Your Hands Before and After Putting Them in The Aquarium

Since fish TB can be transmitted by dirty hands, it’s important to make sure your hands are clean before putting them in the water. Since fish TB and some other fish diseases can also infect humans, some hobbyists prefer to wash their hands after putting them in the tank, too.

Thoroughly clean your hands with soap or use a disinfectant agent to help eliminate pathogens such as Mycobacterium bacteria which could harm your fish.

Treatment of Fish Tuberculosis

The main Mycobacterium marinum bacteria that causes fish TB is difficult to treat because of the unique protective coating that makes it very resistant to medicines. Although some people have successfully cured their fish from some types of Mycobacterium bacteria with antibiotics, treatment is rarely successful.

By the time symptoms become apparent, the infection is usually already widespread and difficult to eradicate.

Sadly, aquarists that have discovered TB in their fish usually only have two feasible options: either isolate their fish and let them live out the rest of their lives with the infection, or euthanize them.

Since fish tuberculosis can be transmitted to humans, many fish keepers regard euthanizing the fish and then thoroughly sterilizing the tank as the only sensible option before the tank can be used again.

Before considering such drastic action, please consult your local exotics vets to get a positive diagnosis.


A bent spine in guppy fish can be caused by several factors including pregnancy, genetic issues, inadequate nutrition, poor water quality, and disease. Sadly, once the spine has been severely bent, it’s usually impossible to straighten it again, and euthanasia may be the kindest option.

When it comes to fish scoliosis, prevention is much more effective than treatment. Keeping your guppies and guppy fry fed on a diverse, vitamin-rich diet, keeping your tank clean, and only breeding from your strongest stock is your best defense against this debilitating disease.

Sharing is caring!


Apparel & Accessories

Beds & Furniture

Cameras & Monitors




Health Supplies

Aquarium Pumps

Aquarium Filters

Aquarium Lights

Aquarium Heaters

A Dog-Loving Resort Manager Rescues Canines in Need
8 Den-tastic Dental Health Tips for Puppies!
Dogo App Review 2024: An Expert Breakdown
Everything You Need to Know About Osteopathy for Dogs and Cats
Funny Cats | Funny Ski Fails
Cake Decorating 101 with Funny Dog Maymo: Yummy Cake Recipe by Dog Chef
Adorable Pets You’ll Just Fall In Love With! Funny Pet Videos 2019
Cat Fails – Funny Cat Videos – Funny Animal Videos 2020