Why Are My Algae Eaters Dying? {5 Possible Reasons Explained}

Are you witnessing your Algae Eaters dying? I thought I was unlucky. What are my algae eater dying?

How do you tell if an algae eater is stressed? Are there ways to prevent this from happening again?

In this article, I’ll run through the reasons why your Algae Eaters are dying and offer some solutions for the future.

Why Are My Algae Eaters Dying?

Stress from tank conditions including water chemistry, illness, lack of space, too much waste, aggression or lack of nutrients are possible reasons why your Algae Eaters are dying.

Your nitrogen cycle, water tests, water changes, appropriate tank size and tankmates will determine if you can help Algae Eaters survive.

What Kills An Algae Eater?

Here are a few conditions that may have killed an Algae Eater:

  1. Too much waste
  2. Lack of oxygen
  3. Not enough food
  4. Aggression 
  5. Illness

1. Too Much Waste

Algae Eaters can make a mess of the tank with the amount of waste they produce. The bigger the Algae Eater, such as a 12 inch long Plecostomus, the more waste will convert into ammonia.

2. Lack of Oxygen

Low levels of oxygen could be causing your Algae Eaters to gulp for air, swim up and down or in erratic patterns. Increase aeration through your filter, air pump, air stones or powerhead and add more plants like Java Moss or Water Wisteria.

3. Not Enough Food

Algae alone may not be sufficient to satisfy the diet of your Algae Eaters. Introduce more protein rich meals like daphnia, larvae, tubifex worms, brine shrimp and vegetables such as lettuce, spinach and zucchini.

4. Aggression

Aggressive tankmates could cause your relatively peaceful Algae Eaters to be spooked where they hide too much or stop eating. Aggression can cause injury or illness as well.

5. Illness

Physical appearances may show abnormal spots, lesions, bloating, discoloration or infection. Look closely to see if your Algae Eater is inflicted with a disease, infection or anything that is treatable.

Why Did My Algae Eater Die?

If you included Algae Eaters in your fish keeping hobby, but were unsuccessful, there are precautions to take for your next time. Let’s start with making sure there is an established colony of nitrifying bacteria.

Ammonia, nitrite and nitrate levels will be kept under control when your beneficial bacteria thriving throughout the tank is converting harmful pollutants into safer nitrogen compounds.

Cycle your tank without Algae Eaters because their skin and internal organs are sensitive during this long and extremely important process.

How Many Algae Eaters Should I Have?

Algae Eaters vary in sizes. Consider the needs of your tank first.

  1. Three algae eaters at a time in 20-55 gallons should be enough to control small levels of algae production that should occur naturally in a cycled tank.
  2. With each additional Algae Eater, the chemical balance including pH, nitrates, nitrites and ammonia will be altered. Test the water and make sure you do not overstock based on the limitations of your tank.
  3. Plecos would need 75-150 gallons minimum while Siamese Algae Eaters should be kept in schools of 3-6.
  4. One inch of fish per gallon is the general rule of thumb, but we tend to go past that mark for messier or larger Algae Eaters.
  5. A 5-7 inch Siamese Algae Eater should kept in a 20-30 gallon tank, but when you add 3 of them together, you should be looking at a tank larger than 55 gallons.
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How Do You Tell If An Algae Eater Is Stressed?

There are some usual signs and signals that act as low level sirens. Our Algae Eaters are trying to show us that they are stressed. Look for the following:

  • Breathing heavily
  • Gasping for air
  • Decreased appetite
  • Nipped fins or wounds
  • Erratic movements 
  • Color changes
  • Discoloration, dull or pale
  • Excessive hiding
  • No activity

Once you determine that your water chemistry is not off, you can assess the problem with your Algae Eaters. Water changes should be done gradually. Algae Eaters seem to get more skittish than most aquatic life during water changes.

Aggressive tankmates should be relocated and tanks must take into account the individual size requirements of each type of Algae Eater.

Will My Algae Eater Starve?

The algae production is welcomed in a balanced aquarium. Nonetheless, it doesn’t serve to provide enough nourishment for Algae Eaters to thrive. Introduce a varied diet of proteins and vegetables.

Keep in mind that a stressed Algae Eater may not wish to eat until harmful conditions are corrected. If there is aggression, insufficient space or lack of hiding areas, it won’t accept much of what you offer.

The waste an Algae Eater can produce is immense for their relative sizes. Make sure you are aware and able to clean it through the filter, gravel vacuum and water changes.

 Why Is My Algae Eater Turning White?

If you notice that your Algae Eater is becoming pale, looking washed out or turning white, you can address its concerns before it’s too late. Your Algae is stressed, fearful or sick. Some reasons for an Algae Eater turning white are mentioned below:

  • disease
  • aggressive tankmates
  • poor diet
  • loneliness
  • improper size of tank
  • poor water quality

Do My Algae Eaters Have Ich?

If the white you see is scattered as spots, you may have an outbreak of Ich in the tank. This protozoan infections causes white spots to attach themselves and grow on Algae Eaters or any other tankmate.

The aquarium must be treated with medication, salt or raising the temperature to speed up the life cycle of Ich and get rid of them. Use half doses of salt or medicine due to the sensitive skin of most Algae Eaters.

What’s Wrong With My Algae Eater?

Are there clear signs that something is wrong with your Algae Eater? Do you see any of the following?

  • Bloating
  • Loss of color
  • Fin rot
  • Cloudy eyes
  • Excessive hiding 
  • Panic swimming

Bacterial diseases such as dropsy or fin rot could indicate a bacterial disease present in your tank. Bloating could indicate dropsy or your Algae Eater could simply be constipated. Shelled peas may help in small portions on the second day.

Take today off from feeding your Algae Eater, but keep observing for any changes. Gradual water changes on your part may help out.


The ecosystem we have created and managed so well could be thrown off when we discover a dead or dying Algae Eater. We may have included too many of them or not had enough space to keep them comfortable.

If your Algae Eaters hide all day, they could be sensitive to aggressive tankmates or spikes of ammonia. The list of possible reasons why your Algae Eaters are dying is extensive.

We try our best to provide enough information to lead you in a direction where you can check off each possible issue one-by-one until you can determine the next step forward. We encourage you to not give up and thank you for making the effort to help your fish.


This is HelpUsFish.com and we’re happy to provide you with many articles surrounding the aquatic life that you’re interested in. See you next time! 

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.