Why Is My Plecostomus Turning White? {6 Ways To Help}

Are you seeing your plecostomus turning lighter in color? Is the whitening of a plecostomus normal or a sign of bigger problems to come? In this article, we’ll find out why your plecostomus is turning white.

Why Is My Plecostomus Turning White? Stress, water parameters, too much light or an insufficient diet could be causing your plecostomus to turn white. Fungal growths or Ich look like white spots. Water changes, supplementing their diets or adjusting pH and water temperature may help solve this issue. 

Is It Normal For A Plecostomus To Turn White?

Although it happens to many plecostomus (plecos) in captivity, when we are noticing the whitening of their skin, we should react to it immediately. Look closely for the following factors:

  • stress
  • poor nutrition
  • illness
  • tank size
  • tankmates
  • water quality

The sooner we act on the obvious physical sign of a plecostomus turning white, the better we can do at preventing illnesses or death.

Is My Plecostomus Stressed?

Stress takes on many shapes or forms. In this instance, the color change into a lighter tan or white color may be an indicator of stress. Please make sure there aren’t any tankmates that are trying to bully your plecostomus out of its food sources or favorite areas to swim and explore.

If your plecostomus  is hiding, not eating or simply disinterested in anything going on, stress is looming and its color may whiten as a result. You can either remove any aggressive tankmates or place your pleco in a quarantine tank for now.

Keep in mind that your plecostomus wants to enjoy dark spaces. Too much light or lack of hiding places may also cause stress. Address all other issues including checking the water quality and making sure your pleco is eating enough.

Is My Plecostomus Getting Enough Nutrients?

Plecos love to eat algae. Most fish keepers want to keep a clean tank and do not wish to allow algae to take on a prominent role in the tank. We get algae eaters like a plecostomus to help get rid of it. Is this enough food for the plecostomus?

Depending on remaining scraps of algae will not suffice. Your plecostomus may be turning white from a lack of nutrients. Try to slowly train your pleco to enjoy the following foods:

  • kale
  • cabbage
  • lettuce
  • zucchini 
  • cucumbers
  • algae wafers
  • shelled peas
  • pellets
  • flakes

Sometimes it takes a while to get a pleco to turn their attention from algae to other rich sources of nutrition, but it’s possible and should be attempted. Make sure the food sinks and stays there with a clip, a stick or tied to a rock at the bottom of the tank.

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Is My Plecostomus Sick?

If your plecostomus is turning white, there is a high probability that it’s getting sick. Is this a full body whitening or only some patches? Is it more like white spots like Ich or a fungal infection?

Look closely to examine the details of this discoloration. Here are some common diseases that could cause your plecostomus to turn white:

  • Dropsy
  • Ich
  • Fin Rot
  • Hole In The Head

Follow These Three Steps Before Seeking Medical Treatment Options:

  1. Fluids build up in the body and the skin may expose it with whitening. Bacterial and parasitic infections could be taking over. Check the gills, fins and all over the body for white spots.
  2. Your tank’s substrate might be infected and your plecos could be the first of your community fish to get exposed to it. Injuries or fin nipping could cause stress or rotting. Vacuum the substrate.
  3. Look at the head of your plecostomus to make sure there are no dents, pits or holes. All of these illnesses require treating the tank or removing your sick plecostomus to treat it separately.

What Are The Water Parameters For Plecostomus?

Make sure that your plecostomus is thriving under the correct water parameters that mimic their South American freshwater environments.

  • Water Temperature: 74-80° F
  • pH: 7.0-8.0
  • Alkalinity: 3-10° dKH (54 ppm to 180 ppm)
  • Nitrates: Less than 40 ppm
  • Nitrites and Ammonia: 0 ppm

Continue to test your water quality before your plecostomus continues to turn whiter. If 2-3 days go by with ideal water parameters and your plecostomus is not recovering, look towards medication or a quarantine tank.

Is My Tank Too Small For My Plecostomus?

Unless you have a dwarf pleco, you will need a very large tank. An average plecostomus may grow up to 15-24 inches. Ideal tank sizes start from 50 gallons and most fish keepers with plecos will recommend 75-100 gallon tanks.

The following plecos can be kept in 10-20 gallon tanks because of their smaller sizes, even at maturity. We lean towards 20 gallons because plecos love to explore.

  • Gold Spot Dwarf Pleco
  • Pitbull Pleco
  • Dwarf Snowball Pleco
  • Angelicus Pleco
  • Clown Pleco
  • Zebra Pleco
  • Queen Arabesque Pleco
  • Bristlenose Pleco
  • Leopard Frog Pleco
  • Rubber Lipped Pleco


There are six ways to help your plecostomus that is turning white:

  1. Reduce stress from aggressive tankmates.
  2. Add more hiding spots away from the light.
  3. Introduce more protein and vegetables.
  4. Look for illness and treat the tank or quarantine your plecostomus.
  5. Test your water quality and keep the parameters optimal for your plecostomus.
  6. Get a larger tank for many types of plecostomus that will continue to grow up to 15-24 inches.

We love plecos for their gorgeous colors and we’re saddened to see them turning white when they are stressed. Let’s keep an eye out for conditions that we can improve or treat to bring back the vibrancy in our beautiful plecos!


Thanks for visiting HelpUsFish.com for another article on plecostomus that we greatly enjoy taking care of in our aquariums. Check out more of our articles on the variety of marine life we research and keep. Bye for now!

Brian Arial

Brian Arial has kept fish for leisure and worked with fish stores for most of his life. He enjoys writing and caring for aquariums and ponds.

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