Pleco Fish Constipation: Causes, Symptoms & Treatment

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Constipation in Plecos is no joke – it’s a genuine issue that can severely affect these water dwellers.

I remember the first time I saw this – I was really shocked and didn’t know what to do. But as time passed, I learned more about it.

In this article, I’ll talk about why Pleco fish get constipated, how to help them, and how to stop it from happening later on.

Let’s jump in.

What Is Constipation in Pleco Fish?

Constipation in Pleco fish refers to a condition where Plecos have difficulty passing feces or don’t pass them at all.

This digestive issue can lead to discomfort and health problems for the fish if not addressed.

  • Dietary Causes: Plecos often get constipated from a diet lacking in fiber. For instance, feeding them exclusively on high-protein pellets can cause this issue.
  • Symptoms to Observe: A constipated Pleco might show a bloated belly, less activity, or have stringy, white feces trailing from its anus.
  • Ideal Diet Mix: To prevent constipation, Plecos should have a mix of vegetables (like zucchini) and specialized pellets; a 70-30 ratio often works best.
  • Treatment Methods: If a Pleco is constipated, offering blanched peas can act as a mild laxative, helping to clear the digestive tract.

Also Read: Pleco Fish Diseases

What Are the Symptoms of Constipation in Pleco Fish?

The symptoms of constipation in Pleco fish are often noticeable through changes in their behavior and appearance.

When Plecos are constipated, it affects their overall well-being and can be evident in several ways.

  • Bloating: A constipated Pleco might show a visibly swollen or enlarged belly, indicating a buildup of waste.
  • Reduced Activity: Constipated Plecos often become lethargic, moving less and showing less interest in their surroundings than usual.
  • Changes in Feces: Look for stringy, white, or unusually long feces trailing from the Pleco, which can indicate constipation.
  • Loss of Appetite: Plecos with digestive issues might eat less or even refuse food altogether, which can be alarming.
  • Hiding Behavior: While Plecos are naturally nocturnal, excessive hiding or avoiding light might be a sign of discomfort.
  • Physical Distress: In extreme cases, Plecos might rub against tank surfaces or display other signs of physical discomfort due to the buildup of waste.
  • Floating Issues: Sometimes, constipated Plecos might have difficulty maintaining their buoyancy and could float near the surface.

Also Read: Pleco Fish Swim Bladder Disorder

What Causes Constipation in Pleco Fish?

There are a few causes for constipation in Plecos:

1. Poor Diet

A diet lacking in the necessary fiber or variety is a leading cause of constipation in Pleco fish. Without the right nutrients, Plecos struggle to maintain healthy digestion.

  • Unvaried Feed: Feeding Plecos only high-protein pellets or the same type of food constantly can lead to digestive issues.
  • Lack of Vegetation: Plecos naturally graze on algae and plants; a diet devoid of such green matter limits their fiber intake.
  • Overfeeding: Providing too much food can lead to waste accumulation inside the Pleco, causing constipation.

2. Lack of Water Movement

Adequate water movement is vital for Plecos’ overall health, aiding in digestion and waste expulsion.

  • Stagnant Water: Areas of still water can lead to reduced oxygen, affecting Pleco’s metabolic and digestive processes.
  • Waste Accumulation: Without proper water flow, waste can accumulate in specific areas, leading Plecos to ingest it back, causing constipation.
  • Decreased Stimulation: Flowing water also stimulates Plecos, and its absence can make them less active, contributing to sluggish digestion.

3. Environmental Stress

Stressful surroundings can disrupt a Pleco’s normal digestive function, leading to constipation.

  • Inadequate Tank Size: Plecos need space. A cramped tank can stress them, affecting their digestive processes.
  • Abrupt Changes: Sudden shifts in water temperature, pH, or other parameters can distress Plecos and impact digestion.
  • Presence of Aggressors: If Plecos are constantly threatened by other fish, their stress levels rise, potentially leading to constipation.

4. Internal Parasites or Infections

Parasites and infections can directly harm a Pleco’s digestive system, causing constipation.

  • Visible Signs: A Pleco with internal parasites might exhibit rapid weight loss or stringy feces.
  • Reduced Immunity: Poor water conditions can weaken Plecos, making them more susceptible to infections.
  • Contaminated Sources: Introducing plants or fish without proper quarantine can bring parasites into the tank.

5. Ingestion of Indigestible Material

Sometimes, Plecos ingest materials they cannot digest, leading to blockages.

  • Tank Decor: If Plecos nibble on plastic plants or decorations, indigestible fragments can cause internal blockages.
  • Gravel and Sand: Larger substrate particles can be ingested, especially if Plecos are searching for food remnants.
  • Foreign Objects: Ensure no foreign items, like stray pieces of plastic or rubber, are inside the tank, as Plecos might accidentally consume them.

How to Treat a Constipated Pleco

To help a constipated Pleco, you need to follow these steps:

1. Ensuring Adequate Fiber Intake

A fiber-rich diet helps prevent constipation in Plecos. A well-rounded intake ensures their digestive system functions optimally.

  • Varied Diet: Rotate foods weekly; for instance, combine algae wafers on Monday, pellets on Wednesday, and fresh veggies on Friday. My recommendation: Invert Aquatics Mini Algae Discs (link to Amazon).
  • Green Vegetables: Feed Plecos blanched zucchini slices or peas; for peas, 1-2 peas per medium-sized Pleco often does the trick.
  • Limit High-Protein Foods: Offer meaty treats, like bloodworms, only once a week to balance the protein intake.
  • Regular Feeding Schedule: Designate feeding times, e.g., 8 AM and 5 PM, to ensure consistent digestion rhythms.

2. Enhancing Water Circulation

Strong water movement supports Plecos’ digestive health by ensuring a well-aerated, clean environment.

  • Invest in Filters: Use filters rated for tanks 10-20 gallons larger than yours; for a 50-gallon tank, get a 60-70 gallon-rated filter.
  • Strategic Placement: Position decorations or plants away from water inlets/outlets to prevent flow blockage.
  • Regular Maintenance: Clean filters monthly; for instance, on every first Saturday, ensuring optimal performance.
  • Aerate: Incorporate air stones or bubblers, ideally one per every 20 gallons, to enhance oxygen levels. I personally got the Hygger Aquarium Air Stone (link to Amazon), and I couldn’t be happier with that choice.

3. Optimizing Tank Conditions

A stress-free environment supports Plecos’ overall health, indirectly aiding their digestion.

  • Adequate Tank Size: For common Plecos, a minimum of 55 gallons is recommended; bigger species may need up to 150 gallons.
  • Stable Parameters: Keep water temperature at 76-80°F and pH levels between 6.5-7.5, checking weekly with a test kit.
  • Hideouts: Provide at least one hideout per Pleco, like driftwood or caves, for them to retreat and relax. My Plecos absolutely love this Dr. Moss Malaysian Driftwood (link to Amazon).
  • Regular Water Changes: Replace 20-25% of tank water biweekly, ensuring the removal of potential waste build-up.

4. Addressing Parasites and Infections

Parasitic infections can directly impact a Pleco’s digestive system, so early identification and treatment are essential.

  • Quarantine New Additions: Always keep new fish or plants in a separate tank for 2-4 weeks to monitor for potential diseases.
  • Anti-Parasitic Treatments: At the first sign of infection, consider medicated foods or treatments, such as Fritz Mardel Coppersafe (link to Amazon), dosed as per instructions.
  • Regular Observations: Dedicate time, perhaps every Sunday evening, to observe Plecos for unusual behaviors or physical changes indicating parasites.
  • Maintain Cleanliness: Vacuum the substrate biweekly to reduce the chance of parasitic eggs or larvae affecting Plecos.

5. Preventing Foreign Ingestion

Plecos might ingest non-food items, leading to digestive blockages, so prevention is paramount.

  • Choose Safe Decor: Opt for smooth-edged, non-porous decorations; for instance, avoid jagged rocks or poorly-made plastic plants.
  • Monitor Substrate Size: Use medium-grained substrates, about 2-5mm in diameter, to deter Plecos from attempting ingestion.
  • Regular Tank Inspection: Set a monthly reminder, perhaps every first Friday, to check for and remove any foreign debris in the tank.
  • Educate Tank Cohabitants: If children or other household members interact with the tank, instruct them on the dangers of introducing foreign items to Plecos.

How to Tell If Your Pleco Is Bloated from Constipation?

If your Pleco appears swollen or its abdomen looks distended, it may be experiencing bloat due to constipation.

It’s crucial to differentiate this bloat from other ailments to provide the right care.

  • Distinct Abdominal Enlargement: A constipated Pleco’s belly will be noticeably extended, more prominent on one side, especially the left when viewed from above.
  • Prolonged Feces Trailing: If there’s a white, stringy, or long fecal matter constantly trailing from the Pleco, this might indicate a constipated digestive system.
  • Reduced Appetite: A constipated Pleco might be disinterested in food; for instance, ignoring a zucchini slice that it’d typically devour within hours.
  • Lethargy and Inactivity: Unlike the active grazing Pleco you’re used to, a constipated one might stay in one spot or hide more frequently.
  • Absence of Other Symptoms: If there’s no visible sign of diseases like ich (white spots) or external injuries, but the bloat persists, it’s likely due to constipation.

What Could Be Other Reasons for Belly Swelling in Pleco Fish?

Belly swelling in Pleco fish, while sometimes indicative of constipation, can also result from other causes.

Identifying the exact reason is critical to offer appropriate care and ensure the Pleco’s well-being.

1. Dropsy

This condition is often more severe than simple constipation, with internal issues at play.

  • Scales Tell the Tale: Unlike constipation, dropsy will often cause the Pleco’s scales to “pinecone” or stick out noticeably. If the scales remain flat, it’s less likely to be dropsy.
  • Uneven Swelling: Dropsy might not cause uniform swelling. If one part of the belly looks more swollen than the rest, consider this over constipation.
  • Tip: Using a flashlight, shine it at an angle towards the Pleco. Dropsy often gives the fish a more translucent look due to fluid build-up, different from the fuller, solid appearance of constipation.

Also Read: Dropsy In Pleco Fish

2. Bearing Eggs

Egg-bearing is a natural occurrence but can be mistaken for constipation due to the swollen abdomen.

  • Texture Matters: Gravid Plecos have a grainy or lumpy texture to their belly, representing the eggs. This texture isn’t present in constipated Plecos.
  • Behavioral Changes: An egg-bearing Pleco might act more territorially or search for hiding spots more than a constipated one would.
  • Tip: Observing for mating behaviors or pairing up with other Plecos can hint at gravidity. If she’s regularly followed by a male or you notice courtship dances, she’s likely gravid.

3. Growths

Tumors or growths can cause abdominal swelling, and these growths might be benign or malignant.

  • Firmness vs. Softness: Growths usually result in a firm area on the Pleco’s body, whereas constipation might result in a softer, more flexible swollen area.
  • Location Specificity: Unlike the generalized swelling of constipation, tumors might cause a localized bulge or lump in a specific area of the Pleco’s belly.
  • Tip: Observe the color and texture of the swelling. Growths often change the skin’s texture and might be discolored, while constipation retains the skin’s normal color and texture.

How to Avoid Constipation in Pleco Fish

Ensuring your Pleco maintains regular digestion is fundamental to its overall health and well-being.

Constipation can be avoided by focusing on their diet, environment, and regular monitoring.

  • Balanced Diet: Feed Plecos a 70-30 mix of high-quality pellets and green vegetables, such as blanched zucchini slices or spinach.
  • Frequent Small Meals: Instead of one large meal, offer Plecos 2-3 smaller meals daily, ensuring they consume the food within 15-20 minutes.
  • Water Quality: Maintain the water’s pH between 6.5-7.5 and the temperature at a steady 76-80°F, as drastic fluctuations can affect digestion.
  • Adequate Tank Size: For a common Pleco, a minimum of 55 gallons is advised. This allows them space to move and aids digestion.
  • Monitor and Adjust: Observe your Pleco’s fecal matter; if it’s too stringy or infrequent, consider adjusting their diet or adding more fiber.

Is Constipation Lethal for Pleco Fish?

Yes, if left untreated, constipation can be lethal for Plecos. However, with early detection and proper care, it’s often manageable.

  • Digestive Strain: Prolonged constipation can cause internal damage to Plecos, like ruptures or blockages, which are life-threatening.
  • Secondary Issues: Constipation can lead to other complications, such as infections or imbalances in their internal bacteria, further jeopardizing their health.
  • Stress and Vulnerability: A constipated Pleco is stressed and might have a weakened immune system, making it more susceptible to other diseases or infections.

Is Offering Canned Peas to Pleco Fish Advisable?

Yes, offering canned peas to Pleco fish can be advisable, but with certain precautions. Peas act as a mild laxative and can help alleviate constipation in Plecos.

  • Blanched and Deshelled: Before offering to Plecos, ensure peas are blanched and their outer shells removed, making digestion easier.
  • Moderation is Key: While beneficial, don’t overfeed peas; a pea segment once or twice a week is often sufficient for medium-sized Plecos.
  • Watch Additives: Opt for canned peas without added salt or preservatives. If unsure, rinsing them thoroughly before use is a safe bet.
  • Natural Alternative: Whenever possible, using fresh peas over canned ones is preferable, as they offer better nutritional value without added chemicals.


For quick readers, here’s a short recap:

  • Plecos often face constipation due to diets lacking fiber, manifested through a bloated belly and stringy feces.
  • Addressing constipation involves a balanced diet, like a 70-30 mix of pellets and vegetables, and maintaining water quality and tank conditions.
  • Bloating in Plecos can also be due to dropsy, bearing eggs, or growths, each with unique identifying features.
  • While constipation can be lethal to Plecos, early detection and proper care, like offering blanched peas, can mitigate its effects.
  • Introducing canned peas to Plecos can be beneficial; however, ensure they’re blanched, deshelled, and free from additives.