10 Signs of a Dying Pleco and How to Save It at Home

Plecostomus, affectionately known as the pleco, is an enigmatic fish known for its algae-eating ability. While pleco fish are generally hardy fish, plecos are not immune to diseases and can die from infections. Therefore, knowing the signs of a dying pleco will help you devise the appropriate solution to save your fish.

It’s disheartening to see your Plecostomus fish inactive in the aquarium. Many aquarists fail to notice when their plecos are sick and dying because of the ignorance of sick pleco’s symptoms. This is a challenge to saving a dying pleco fish. If you can’t notice signs that your pleco is dying, you’ll not be able to take the necessary urgent interventions to save her.

The main signs of a dying pleco are frayed fins, lethargy and inactivity, mucus and white spots on the body. When you notice these signs, it’s time to take the necessary measures to save your fish. You should start by checking the tank’s pH before contacting a veterinarian.

Most aquarists do the following to ensure the safety of their plecos:

  • Ensuring good hiding places for their plecos in the aquarium
  • Giving them a varied, balanced diet
  • Keeping an eye on the water parameters in the aquarium

While these are great tips, they won’t help you if you don’t know the signs of a dying pleco. Today, you’ll know 8 of your sick pleco’s symptoms.  Furthermore, you’ll get tips on how to save a dying pleco fish.

1. Frayed or Torn Fins

Signs of a dying pleco
Pleco with frayed fins

If your pleco has Frayed (rot fin) or torn fins it might be a sign of a bacterial infection which is a common pleco disease. The disease is exacerbated by poor water quality. The fins will gradually become shorter and thinner as the disease progresses.

Before the fins start getting fray, you’ll see white spots on the fins. The white spots are a result of tissue damage. The bacteria will then start to eat away at the fins, causing them to fray and tear.

You can diagnose fin rot in your pleco fish by:

  • Inspecting the fins for white spots
  • Checking if the edges of the fins are black
  • Fins falling off in large chunks

If you notice these signs, you must act immediately to save your dying pleco. Bacterial diseases in pleco are easy to control because they’re caused by poor water conditions in the tank.

Remedies to Frayed or Torn Pleco Fins

To prevent the circumstance of a dying pleco, The first step is to do a water test to check if the nitrogen cycle is at optimum. The nitrogen cycle in fish aquariums is determined by ammonia, nitrite, and nitrate levels

For a conducive environment for your pleco in the aquarium, ensure that the levels of these components are as indicated in the table below:

Component0 to 2 Weeks2 to 4 Weeks5 to 6 WeeksComplete
Ammonia<0.06 ppm0.0 ppm0.0 ppm0.0 ppm
Nitrites0.0 ppm<0.75 ppm<0,75 ppm0.0 ppm
Nitrates0.0 ppm0.0 ppm25.0 ppm25.0+ ppm
Optimum nitrogen cycle conditions in a fish tank

If you notice that the levels of ammonia, nitrite, and nitrate in your pleco tank do not adhere to the above standards, take the following steps:

  • Improve the water quality: Do a 25% water change as soon as possible to ensure that the water has enough nitrifying bacteria that eat ammonia. (N/B: If you don’t know how to do a 25% water change in your fish aquarium, check for a guide at the end of this article).
  • Add an aquarium filter: The filter will help remove toxins and pollutants from the water.
  • Add aquarium salt: This salt helps reduce the stress levels of your pleco. It also aids in the healing process of your fish’s fins.
  • Add an air stone: This helps increase oxygen levels in the aquarium by aerating the water.
  • Use pleco cave: This is a hiding place for the pleco. It will help your pleco feel safe and secure.
  • Increase filtration: This will help remove toxins and pollutants from the water.

After taking these steps, you should see an improvement in your pleco fish’s fins. If not, consult your veterinarian immediately to save your dying pleco.

2. Lethargy and Inactivity

Pleco fish lying at the bottom of the tank

Plecos are active fish that constantly swim around the aquarium. So, when you see your pleco swimming less or not at all, it could be a sign of a dying pleco. Most of the time, a lethargic pleco will be seen lying on its sides.

In some instances, you may notice the pleco fish swimming upside down.

Lethargy and inactivity in plecos are caused by many factors, including:


Plecos are not immune to diseases.Sick pleco symptoms include signs of lethargy and inactivity because most of its energy is used to fight the disease. Common pleco fish diseases include:

  • Epistylis (Heteropolaria): This is a common bacterial disease that affects pleco fish. The disease is characterized by the formation of white spots on the body of sick fish.
  • Hexamita (White Spot Disease): This is a parasitic infection that affects the intestines of fish. The parasites cause ulcerations and inflammation in the intestines, which leads to lethargy and inactivity.
  • Aeromonas (Black Spot Disease): This is a bacterial infection that affects fish’s skin. The bacteria cause black spots to form on the skin of the fish.

If you notice some of the mentioned signs, the best remedy is to consult your vet. Early diagnosis and treatment of diseases can save your dying pleco fish.

Poor Water Quality

Pleco fish are susceptible to changes in water quality. So, if the water in your aquarium is not of good quality, it will affect the health of your pleco, which may make it inactive.

Some of the signs of poor water quality in the aquarium include:

  • Bad odor: This is a sign that there is too much ammonia in the water.
  • Cloudy water: This is a sign of high nitrite levels in the water.
  • Algae growth: High phosphate levels in the water.

If you notice any of these signs, you should do a 25% water change immediately.


Plecos are sensitive to changes in their environment. If they’re not comfortable in their surroundings, they will become stressed. Stressed plecos are inactive and may stop eating.

Therefore induced stress can be a cause of a dying pleco.

So, if you notice that your pleco is inactive, the first thing you should do is check the water quality. If the water quality is good, then the problem might be stress. To reduce fish stress, do the following:

  • Add aquarium salt: Aquarium salt helps reduce the stress levels of your pleco fish by reducing the osmotic pressure in their body.
  • Add an air stone: This helps increase oxygen levels in the aquarium, reducing stress in fish.

Poor Diet

Plecos are omnivores, which means they need a balanced diet of meat and plants. Poor nutrition leads to malnutrition in plecos.

A balanced pleco diet must include:

  • Sufficient fiber: Raw vegetables, carrots, raw zucchini, lettuce, cucumbers.
  • Protein: Shrimp pellets, bloodworms, brine shrimp, or krill.
  • Algae Wafers: Are excellent for plecos.
  • Lignin and cellulose: Driftwood.

3. Mucus or Strange Growths on the Body

Pleco’s body is covered with mucus which protects it from diseases and parasites. If you notice that the mucus is thick and has strange growths, it’s a sign that your pleco is dying.

Bacterial infections like Lymphocystis or parasites might cause the thick mucus. The growths might be caused by tumors or cysts.

The growths on a pleco are generally small to moderate, nodular, irregular, or wart-like. They can be on the gills, skin, or fins. Mostly, these growths are cream to grey. They can also be in other colours if they appear in pigmented regions.

The best way to handle such signs in your pleco fish is by consulting a vet. It’s not easy to know the exact cause of the mucus or growth without a professional opinion.

4. White Spots on the Body (Ich)

Signs of a dying pleco
Pleco on close-range

White spots on the body of your pleco fish are a sign of ich. Ich is a parasitic infection in a pleco that affects the skin of the fish. The parasites cause white spots to form on the skin of the fish.

The white spots on the pleco’s body are cysts that contain the parasite. When the cysts burst, the parasites release into the water and attach themselves to other fish.

Ich is a common occurrence among tropical fish like plecos and is highly contagious.

In most cases, parasites that cause ich thrive in poor water conditions with excess ammonia.

If you notice one of your pleco with white spots, remove it from the tank immediately. This will prevent the parasites from bursting and spreading to other fish. Furthermore, you must do a water change to safeguard the health of the other fish.

After isolating the fish, monitor the water levels, pH, and nitrogen cycle. If the ammonia and nitrite levels are high, do a water change.

Quarantine the sick pleco in a separate tank with a high temperature. The high temperature will help kill the parasites and stop them from spreading. Finally, you must consult a vet for proper medication for such an ailment.

5. Floating at the Surface of the Water

A pleco floating uncontrollably on the water’s surface is an indication of a malfunction of the swim bladder.

Swim bladder is an organ in fish that helps maintain their buoyancy.

The moment you wake up to the stunning sight of your pleco looking like a balloon on the water’s surface, know that something is not right. This could be a sign that your pleco is dying.

You should check to ensure that the fish is not dead. Apart from floating, the fish might be swimming upside down and occasionally hanging at the bottom.

Your little buddy swimming upside down is an indication that the condition has been going on for some time. Thus, this signifies that your pleco is dying, and you must act immediately. The early signs of this condition include a pleco fish swimming sideways or nose-down-tail-up posture.

It’s worth noting that swimming with a belly up is a common trait in some fish species like the catfish. Therefore, it should not be taken as a sign of sickness in such fish. However, in a pleco, this could be a sign that they are dying.

The leading causes of swim bladder infections in pleco fish include:

  • Pressure from a swollen belly: The pressure usually results from overeating or constipation.
  • Injury: This could be from a collision with another fish or object in the tank.
  • Tumors: Tumors in the abdominal area can put pressure on the swim bladder and cause problems.
  • Too much air swallowed: This is a common cause of swim bladder problems in goldfish. It occurs when the fish gulps excessive air at the surface of the water.
  • Bacterial infections: This is a less common cause of swim bladder infections. It occurs when the fish’s immune system is weak, and bacteria attack the organ.

Remedy for Pleco Fish Floating on Water

The best way to cure your pet fish of this condition is to transfer it to a hospital tank immediately. After that, investigate the reason behind the bizarre behavior.

Ensure that the water in the hospital tank is checked regularly and maintained at the right levels for your dying pleco. The quality of the water must also be standard. After meeting these conditions, embark on the treatment.

The treatment to save your dying pleco fish may take several days. Below are some of the treatments based on the cause of the floating behaviour.

Treating Constipation

If you notice that your pleco fish floats because of constipation, give it an Epsom salt bath. The bath helps to relieve constipated fish. Below is a procedure for the treatment:

  • Add two tablespoons of Epsom salt for every gallon of water in the tank. After that, let your pet fish soak in the solution for about 15 to 20 minutes.
  • After the Epsom salt bath, feed your pleco food high in fiber like cucumbers, cooked pea, or zucchini. These vegetables help to regulate the digestive system and prevent constipation.

Killing Swim Bladder Bacteria

Bacterial infection results in the bladder being filled with fluid.

The best way to diagnose if your fish’s bladder is filled with fluid is by consulting a veterinarian. The vet will use pneumoconiosis ultrasound technique to detect the presence of fluid in the bladder and recommend the best medication.

Do not be like most aquarists who rush to treat their fish with antibiotics without proper diagnosis. You might worsen the condition of your dying pleco.

Swallowing Too Much Air

Bloating in fish is caused by gulping too much air at the surface of the water. The condition is caused by feeding non-sinking foods like live foods and pellets.

The best way to prevent your fish from bloating is by feeding it sinking foods. Sinking foods force the pleco to swim down to the bottom of the tank to feed, reducing the chances of gulping air.

Some of the best sinking foods for pleco include algae wafers, zucchini, and cucumber. You can also give your fish live foods like brine shrimp, blackworms, and bloodworms.

Furthermore, ensure that the tank has a proper filtration system. The filter helps to aerate the water and prevent your fish from gulping air.

6. Cloudy and Pop Eyes

While cloudy eyes are not a direct sign that your pleco is dying, they indicate a serious underlying health problem. You may think that your fish’s eyes have a film or a white cast.

Cloudy eyes go hand in hand with Popeye in fish. Pop eyes occur when there is pressure on the eyeball, and it pops out of its socket. The condition is mainly caused by an injury, tumor, or exophthalmos.

In a pleco, cataracts also contribute to these conditions. They are a result of old age or poor nutrition. Cataracts cause the lens of the eye to become opaque, affecting the fish’s vision.

In fish, cloudy and pop eyes are mainly caused by poor tank conditions like high ammonia levels. The condition can also be caused by an injury that leads to bacterial infections.

The best way to treat these conditions is to find the cause and correct it. Check for tank aggressions, water conditions, and the nitrogen cycle within the tank.

Do not forget to consult a vet to confirm whether the fish has a bacterial infection.

7. White and Stringy Stool

Pleco’s stool usually is black and firm. However, the white and stringy stool is a sign of a parasitic infection. The parasites are usually found in the intestines, interfering with the digestion process.

As a result, your pleco may suffer from malnutrition or dehydration. To confirm if your pleco has parasites, take a sample of its stool to the vet for analysis.

The vet will prescribe the best medication to treat the parasites. In most cases, the vet will recommend a course of antiparasitic drugs.

8. Pleco Scratching Itself Against Objects in the Aquarium

Scratching is typical behavior among plecos. However, if the fish is scratching itself more than usual, it could signify parasites or poor water conditions.

The first step is to check the water parameters in the tank. The ammonia, nitrite, and nitrate levels should be at 0 ppm. If they are not, correct the water conditions immediately by doing a water change.

If the water level and components are okay, the next step is to check for parasites. Take a sample of the fish’s stool to the vet for analysis. The vet will prescribe the best medication to treat the parasites, if any to save your dying pleco.

9. Pleco Fish Gulping at the Surface

If you notice your fish gulping at the tank’s surface, it’s a sign of a dying pleco.

It’s worth mentioning that while gulping is normal for other fish species like cory, it’s not normal for plecos to come gulping at the water’s surface.

The main reason you may see your pleco gulping at the tank’s surface is lack of sufficient oxygen. The fish comes to the surface of the water to search for oxygen, hence the gulping behavior.

Insufficient oxygen usually results from high ammonia nitrite levels in the water. It can also be due to high water temperatures. Remember, the amount of dissolved oxygen in water is inversely proportional to temperature. Therefore, the oxygen level reduces as the water temperature increases, and vice versa.

10. Swollen Belly

A pleco fish with a swollen belly should worry you the most.

Swollen bellies (bloating) in plecos often point to:

  • Poor water quality
  • Overfeeding that leads to constipation
  • Inappropriate diet
  • Parasite and bacterial infection

Parasite and bacterial infections in plecos are the most lethal. If this is the cause, it’s recommended to consult your aquatic veterinarian to save your dying pleco.

How to Save a Dying Pleco Fish

As demonstrated, most of the issues with pleco fish arise from water levels and conditions in the aquarium.

The following are ways you can save your dying pleco fish:

  • Check the water parameters in the tank and correct them if necessary. pH, chemical, and temperature levels contribute a lot to poor water conditions. Checking these parameters will allow you to identify the cause of your fish issues. Ensure the water temperature is between 72 and 78 degrees Fahrenheit. If these parameters are not as they should be, it’s recommended to do a 25% water change weekly.
  • Use Maracyn Two to treat fin rot. The product is readily available in pet stores.
  • Consider using a pleco cave or some other hiding place in the tank. This will give your fish a sense of security and help it to feel more comfortable.
  • Use live foods like bloodworms to boost your fish’s appetite. Live foods are also suitable for their health as they contain all the nutrients the fish need.
  • Consult a vet to get a professional opinion on the best way to save your dying pleco fish.

How to Do a 25% Water Change

As demonstrated, doing a water change is an excellent way to ensure the highest water standards in a fish aquarium.

Veterinarians are against complete water change because it destroys the essential bacteria that aid the survival of the fish. This can also shock your pet’s system and give rise to signs of a dying pleco.

A 25% water change is recommended for large fish tanks. It should be done once per week. Follow the below procedure:

  1. Siphon out dirt using a gravel siphon: This should be done before adding new water to the tank. Put the tube end of the siphon into a bucket and the siphon’s tip into the tank’s substrate at an angle. This allows water and debris to be drawn from the tank.
  2. Suck water from the tank using the siphon: Before sucking, check the water level in the tank from the calibration. Suck 25% of the water in the aquarium into the basket.
  3. Add fresh, dechlorinated water: Use a water conditioner to remove the chlorine from the tap water. Dechlorinating the water is essential because chlorine is toxic to fish. Fill the tank with this water to attain the initial level.
  4. Check the water temperature and pH in the tank to ensure they’re correct.
  5. Monitor your fish for the next few days to ensure they’re okay.

The table below summarizes the signs of a dying pleco, causes, and remedies.

Frayed/torn fins-Poor water conditions
-Bacterial infection
-Check water conditions and adjust accordingly
-Use Maracyn two to treat the fins
Lethargy/inactivity-Diseases (Epistylis, Hexamita)
-Poor water quality
-Poor diet
-Fix the poor water conditions
-Feed the fish high fiber foods like vegetables
-Isolate the fish
Mucus/strange growths on the body-Tumors
-Bacterial infection
-Check the water levels and adjust accordingly
-Isolation treatment
White spots on the body/ich-Stress
-Poor water conditions/level
-IsolationIch treatment
-Check water conditions and adjust accordingly
Floating on water-Swim bladder infection
-Poor water conditions
-Swallowing too much air
-Transfer it to a hospital tank
-Check and fix water problems and level
-Feed the fish sinking foods
-Pneumocentesis treatment
Cloudy and pop eyes-Pressure on the eyeballs
-High ammonia in the tank
Check and rectify:
-Tank aggressions
-Water conditions
-Nitrogen cycle
White and stringy stools-Parasitic infection-Antiparasitic treatment
signs of a dying pleco, causes, and remedies


Pleco fish are great additions to any aquarium. They’re peaceful, beautiful, and easy to care for. However, plecos are sensitive creatures and they can get sick easily.

Therefore it is important that you do not ignore signs of a dying pleco as early intervention can save its life.

To ensure good health for your fish pet, provide a good aquarium environment for it. This is an environment with:

  • The correct water parameters
  • A pleco cave or hiding place
  • Live foods
  • Good tankmates

Most importantly, keep an eye out for the above signs of a dying pleco. This is crucial because you’ll be able to treat the illness before it gets out of hand. With proper care, your pleco will thrive and bring you years of enjoyment.

Frequently Asked Questions

When Plecos die do they float?

Yes. Plecos float when they die because of the gas build-up in their intestines. This is caused by the bacteria decomposing the food in their stomachs.

How to revive a dying pleco?

The best way to revive a dying pleco is by doing a water change and ensuring the correct water parameters. You can also use products like Maracyn Two to treat fin rot. Finally, ensure you consult a vet to prescribe the best treatment for your pet fish. Note that these guidelines are not guaranteed to revive your dying pleco.

How can I tell if my pleco is happy?

You can tell if your pleco is happy by its behavior. A happy pleco is an active fish that is constantly exploring its surroundings. It will also have a good appetite and be alert when someone approaches the tank. Another way to tell if your pleco is happy is by its coloration. A healthy pleco has bright colors and clear eyes.

Why does my pleco have white patches?

White spots on the body of your pleco fish are a sign of ich. Ich is a parasitic infection that affects the skin of fish. The parasites cause white spots to form on the skin of the fish.

If you notice these spots on your pleco fish, isolate the fish immediately. After isolating the fish, monitor the water levels, pH, and nitrogen cycle. If the ammonia and nitrite levels are high, do a water change.

Is my pleco dead or sleeping?

Distinguishing between a dead or sleeping pleco is crucial even though the differences are subtle.

A sleeping pleco is usually near the surface and you can see the movement of the gills. On the other hand, a deceased pleco will float in the water due to the gas buildup and will not respond to any stimulus. 

How to tell if my pleco is dead?

If your pleco is floating in the tank and has been immobile for a while, Chances are that your pleco fish is dead. 

3 thoughts on “10 Signs of a Dying Pleco and How to Save It at Home”

  1. My pleco jumped out of her tank yesterday. She seemed to be swimming fine and acting normal today, until a lid was being placed on the tank. She swam fast side to side then jumped again. She acted as if she was spooked I was told. Then she jumped again hitting the lid, and now she seems to be having a hard time latching on to the glass and it looks like she is thrashing/ shaking. What do I do? Please help! I hate seeing her like this.

  2. My pleco keeps thrashing around the tank wildly and it was staying at the top of the tank I checked the ph level and I saw it was low so I treated the water to rise it up, and the aeration wasn’t the best and I added some bubbles to help break the surface area to help more oxygen come in but he still didn’t seem to improve. I’m not sure if it just takes a few days but I’m not sure what else to do, he also seems to be always sideways and his body is curved in a weird angle, could this be a sign of parasites? There are no other tank mates in his tank and I took out his log he usually hides in because he would run into it will he went crazy, and an update to him is that he is now at the bottom of the tank but he isn’t lying straight. Do you know which I should treat him for?


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