Guppy Tail Drooping: Treating Bent Guppy Fish

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There are days in which I get worried about what I see in my fish tank. For example, one day, I noticed that my guppy’s tail was drooping, and the whole fish appeared bent and ill. To make sure the situation doesn’t spread in my tank, I started to investigate the reasons for the phenomenon quite extensively.

Guppies’ tails typically droop due to environmental factors, such as high ammonia, nitrates, and nitrites. However, guppies may also appear bent due to direct injuries or underlying diseases, such as Scoliosis and Tuberculosis. Those will cause the guppy to bend down and appear with a broken back.

As we move forward, I will share what steps you should take once you see a guppy with a bent tail or spine. Following those steps may prevent further fish from catching the same diseases and deteriorate.

Also Read: Stress In Guppy Fish

Why Is My Guppy Tail Drooping & Seems Broken?

If your guppy has a drooping tail, the creature’s spine is probably bent. However, that isn’t always the case. Sometimes, a drooping tail is merely a sign of distress in fish. You have to look for additional symptoms to determine the reasons definitively. A bent spine is a significant problem in fish because it will compromise the guppy’s quality of life. 

Some potential sources of curved spines and drooping tails in guppies include:

1. Stressing Environment

Some aquarists tend to downplay the impact of stress on fish. Nevertheless, a stressful environment could be responsible for a multitude of diseases in fish. A drooping tail is just one symptom among many that could manifest if your guppy is allowed to struggle with the burden of stress.

Common causes of stress include low water quality, high concentrations of toxins like ammonia, overcrowding, and small tanks, to mention but a few. You can assume that your guppy is stressed if you identify additional symptoms such as clamped fins, timidity, and appetite loss. 

Stressed guppies also spend a lot of time hiding. They are less likely to emerge during meal times. If your guppy is stressed, its tail is likely bent, although the spine itself should be okay. That phenomenon resembles what happens in dogs that aren’t feeling well.

Also Read: Why Do Guppies Blow Bubbles?

2. Old Age

Age is another factor that people either downplay or ignore altogether. Some fish’s bones can become weaker as they age, especially if they are kept in soft water that doesn’t have enough minerals. As a result, they will develop a curved back over time.

The average lifespan of guppies varies, although it is somewhere around two years.[1] If you had your guppies for over a year now, they are probably getting old. In that case, a bent spine is quite common, and there is little you can do about it.

3. Pregnancy

Guppies are livebearers, that is to say, they give birth to live fish. Any element that exerts pressure on the back can contribute to a bent spine in fish. One such element is pregnancy. The presence of fry in a pregnant guppy might not stop at merely distending the belly. 

It could also affect the fish’s spine, leading to a curved back and a drooping tail. That, naturally, occurs in female guppies, which are relatively larger than males. You will typically see a pregnant guppy with a spine that is getting gradually bent.

After delivery, the pressure on your guppy’s back is reduced, although the spine won’t necessarily get back to its original state. The damage could be permanent, and the guppy will try to survive in its new state.

4. Scoliosis

Scoliosis forces the spine to take on an ‘S’ (or ‘C’) shape. The disease commonly appears in fry, though you will also find it in adult guppies. Scoliosis can manifest as a result of inbreeding, poor tank conditions, and bad food. 

Some fish inherit the illness, as most young guppies whose mothers had Scoliosis will eventually develop the disease. Some guppies may carry the disease genes, although they will only develop Scoliosis if the tank’s conditions are inadequate.

5. Tuberculosis

Humans are not the only creatures that suffer from tuberculosis. Mycobacterium marinum causes the disease in fish. The presence of tuberculosis in a guppy should worry you because it is highly contagious. In the past, tuberculosis has been connected to dirty, overcrowded, and poorly maintained tanks. 

However, it is now known that the disease also appears among fish in clean, well-maintained aquariums. One might introduce it to your aquarium through new fish that are carrying the ailment.[2] Tuberculosis causes appetite loss, discoloration, and a loss of scales. It will also curve the spine of the infected guppy. 

The infection may also involve internal organs such as the liver, kidney, and spleen. Externally, you will notice signs of lethargy, fin, and scale loss, and edema. However, since the disease also involves the muscles, you might see deformed, bent fish.[3]

6. Direct Injury

A traumatic collision with the objects in the tank, or a fight with its tankmates, can injure your guppy, causing the spine to curve and the tail to droop. That could also happen when you make water replacements and accidentally hurt your guppy during transfers.

However, that case is pretty rare. Fish are quite hardy and flexible creatures that can endure collision and pressure. A bent spine due to injuries is more likely to develop once infections spread after nibbling, although it usually doesn’t happen.

Also Read: Guppy Laying At The Bottom

How to Treat Bent Guppies with a Drooping Tail?

If your guppy has a curved spine and a drooping tail, you are encouraged to remedy the creature’s situation immediately. Guppies with a bent spine are vulnerable to attack and cannot fight back against bullies. Not only is their quality of life reduced, but their ability to swim is compromised.

Your ability to treat drooping scales and bent spines in guppies will depend on the cause:

1. Tuberculosis

Because bacteria cause this disease, you can fight it with antibiotics such as isoniazid and neomycin. There is also doxycycline, minocycline, and rifampin.[4] Unfortunately, the probability of these drugs working is relatively low, which is why many experts will encourage you to quarantine the fish as you look for ways of humanely euthanizing it.

If you still wish to fight the infection, I highly recommend consulting veterinarians. They will be able to prescribe the right antibiotic and instruct you on the right dosage. Either way, make sure that you isolate the sick guppy to avoid affecting the rest of the tank.

While it sometimes makes sense to expose diseased fish to salt baths, they won’t work in this case. You should also avoid raising the temperature. An elevation in temperature will enhance the bacteria’s activity, making your guppy’s situation even worse.

Quarantine the sick fish and treat it with antibiotics, while maintaining a healthy and balanced diet. If these steps fail to produce tangible results, euthanize the fish. As was noted above, tuberculosis is contagious. 

If one guppy is sick, the chances that the other fish in the tank contract the disease are relatively high. It would help if you watched them in the days and weeks that follow. If some of them start showing symptoms, take the necessary steps to quarantine and treat them.

2. Scoliosis

Scoliosis isn’t contagious. However, the disease is incurable. You cannot treat a guppy whose spine is bent from Scoliosis. Fortunately, the average fish can live a long life despite the physical consequences of Scoliosis. Still, you can prevent the ailment from taking root in your aquarium by avoiding inbreeding.[5]

You may do that by either eliminating fish that have Scoliosis or preventing them from breeding and improving tank conditions. However, if your guppy is suffering because of this disease, your only practical option is to euthanize it.

If you have decided to euthanize your fish because of a bent spine, add clove oil to the tank.[6] In a high concentration, clove oil, which acts as a sedative, will lead to death in less than ten minutes. That is one of the most humane approaches available.

If you wish to keep your fish and let it live as it is, make sure you improve your tank’s conditions. If your guppy enjoys its environment, its chances to move on with the conditions are relatively high. Follow the next step to get a better idea of how to do that.

3. Tank & Water Maintenance

Maintaining the appropriate conditions in a guppy tank will protect your fish from diseases like tuberculosis and enhance their recovery rate. Guppies need a pH of 6.8 to 7.8, a temperature of 72 to 82 degrees F, and water hardness of 8-12 dGH.[7]

The ammonia and nitrite levels should be kept at 0 ppm, and the nitrate levels should be less than 10 ppm. To achieve that, I highly recommend getting the API Aquarium Test Kit (link to Amazon). That highly affordable bundle will accurately measure your pH, nitrates, nitrites, and ammonia within minutes.

If the toxins are too high or the pH is lower than 6.8, you should perform more frequent water changes. Start by replacing 15-20% of the water weekly. I also recommend cleaning your aquarium correctly. Make sure that you remove debris and leftovers from the substrate.

Also, guppies should be kept in tanks of at least five gallons. The more guppies you have, the bigger the required tank. Avoid overcrowding at all costs. Filters and heaters are essential, and so are regular water changes.

Guppies should be fed a varied diet that includes live and frozen foods, flakes, and vegetables. Feed them once or twice a day. To avoid overfeeding, provide them with the amount they consume within two to three minutes.

Guppy fish also require plants and decorations in their environment, and you are better off keeping them with peaceful tankmates such as platies and mollies.[8] But if your other fish have aggressive tendencies, your guppies can still live happy lives if they have places to hide.

4. Salt the Water

Salt won’t help fish that have tuberculosis. However, you can still use it to treat other illnesses. At the very least, it can work as a preventative measure. Salt also makes bacteria and parasites more vulnerable to drugs.

The best way would be to isolate the sick fish in a hospital tank. Then, add one tablespoon of salt to each gallon of water the tank contains (more than that might dehydrate your guppies). To achieve the best result, I suggest using the API Aquarium Salt (link to Amazon).


If the water conditions in your tank are low, your guppy’s tail is likely to bend down. Hence, the first steps you should take will involve testing your water for ammonia, nitrates, and nitrites. You should also check the pH and temperature and see if they fit the guppy’s requirements.

However, if your guppy’s spine is entirely distorted, your fish might be suffering from an underlying disease such as Scoliosis or Tuberculosis. In this case, you should quarantine your fish and consult a veterinarian.

If the cause is indeed tuberculosis, your guppy could be cured using antibiotics (although the chances for that are relatively low). Nevertheless, if it suffers from Scoliosis, you should let your fish live as it is, or consider euthanasia.