Pleco Not Moving? Top 5 Reasons To Know (+What To Do!)

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It is natural to worry when you find your pleco not moving.

Usually, If you don’t notice any dying signs in your pleco (which I’ll be sharing in the ahead sections), there’s nothing to worry about – your pleco is fine!

But still, it is good to know all possible reasons so you can be aware and take action accordingly. So read on till the end to learn more.

Here’s Why Your Pleco Is Not Moving

The most common reason a pleco is not moving is it is resting, hiding, or exhibiting its common behavior. However, sometimes it can stay still when stressed or lack regular movements when about to die.


#1. Common Behavior

Usually, for plecos, it is common to not move and stay still for long. The moment you try to disturb them with a fish net or something, you’ll see them darting away.

“We have had a pleco in our home aquarium. He did the same thing. The pleco used to love his driftwood a lot. And most of the time we watched the pleco, it just stayed still in a spot – busy sucking his driftwood.”

What To Do? If your pleco stays still, spend a bit more time observing; it is likely to suddenly move towards other decorations in the tank. It is fun to watch, and there is nothing to panic about when you see this behavior. 

#2. Sleeping


Another reason why your pleco is not moving is that it is resting. It is a normal behavior in fish to remain still when they sleep. During this time, their breathing slows down.

And plecos don’t have eyelids like us. So when they rest, their sleep appears a bit different than we do. On top of that, plecos are nocturnal

Usually, most fish species are diurnal, which means they are active in the daylight hours, but rest at night. 

However, with nocturnal fish species like pleco, that is the opposite. They spent most of their daylight time in crevices or other hiding places.

What To Do? So the next time you see your pleco inside a cave or other hiding place staying still and breathing, don’t worry – it is likely resting.

#3. Stressed

The next likely reason when you observe your pleco not moving is when the fish is stressed. It more commonly happens when you add the pleco for the first time to your tank or change its environment.


Whenever plecos are introduced to a new tank, there occurs a change in their surrounding environment and water parameters. 

It is not always possible that the water it was previously living in is the same as the one it is now introduced to.

And even a slight environment change can put a fish under stress, including your plecos. 

Hence, it is also important to gradually introduce your pleco to a new tank – known as acclimating. Otherwise, your pleco can experience a shock.

Loss of appetite and discoloration are some things that can occur due to the shock.

So if your pleco is just newly added to the tank and it is not eating, the most likely cause is the experience of shock.

What To Do? Add water conditioners that can reduce stress in the fish.

For instance, I highly recommend getting the API Stress Coat Aquarium water conditioner (available on Amazon).

This product helps in reducing fish stress and also heals any damaged fish tissue. You can use this API stress coat in any of the following conditions:

  • Adding new fish to the tank.
  • When the fish is sick or injured.
  • When you do a water change in the tank.

Another way to reduce stress is to add enough hiding places in the tank. 

Driftwood is one of the best hiding places you can add to your pleco tank. You can add a driftwood like this one (available on Amazon).

Moreover, plecos also feed on driftwood, providing them with the required nutrients that help them in digestion.

In our home aquarium, we have driftwood, and 8 out of 10 times, we spotted the pleco munching on driftwood.

Other than all these, follow all general care principles like providing enough tank space and maintaining adequate water temperature and parameters.

Related Read: How Many Bristlenose Plecos In A 30 Gallon Tank?

The next time you want to introduce a new pleco to the tank, first immerse it in the tank while it is still in the plastic bag. That way, your pleco could adjust to the water temperature. 

Watch this video to learn more about how to acclimate a new fish in a tank:

#4. Hiding

If your pleco is still, it can mean it is simply hiding. As we saw earlier, plecos are nocturnal. So whenever there is daytime, they will look around for hiding spots in the tank to go inside and rest.


Usually, most plecos species love places such as caves, burrows, and crevices. For instance, fish belonging to the Pterygoplichthys genus tend to create burrows alongside the riverbank where they can rest in the daylight hours. And then come out during the night for food.

Then there are other plecos like the Sailfin Pleco – they love to spend a considerable time hiding under caves or driftwood.

What To Do? If you find your pleco hiding and staying still, and you are sure it is not stressed or sick, there’s nothing to worry about.

If a tank mate is harassing your pleco, try separating that tank mate to let the pleco calm down. And you can also get more hiding places for pleco so they can feel relaxed.

#5. Dying

Unfortunately, lacking the usual movements in the tank or laying on the side is one of the signs your fish could be dying. So it is essential to be sure whether your pleco is dying or not and act accordingly.

Before I tell you the possible reasons why a pleco can die, let’s discuss some potential signs to look out for.

How To Know If My Pleco Is Dying?

If your pleco is not moving and you see any of the following signs – the pleco could be dying. 

  • Turning White or Loss of Color
  • Overall Lethargy and Laying On Side
  • Abdominal Swelling
  • Cloudy Eyes
  • Pop Eyes
  • Fin Rotting
  • The appearance of White Spots On the Body

However, if you don’t notice such signs, there’s no panic, and your pleco is fine.

Why Do Pleco Fish Die?

The most common reason a pleco would die is starving. Generally, it is assumed that the algae in the tank is enough for them to feed. But the thing is, they also need proper feeding.


It’s very easy to overlook the food demands of your pleco. But once they don’t get enough food, their body weakens, ultimately starving to death.

Typically, your pleco needs to be fed daily or every other day.

  • You can feed algae wafers once a day. (It is good if you provide the wafers at night)
  • While, you can feed items like zucchini once a week.

For algae wafers, I highly recommend the Hikari Algae Wafers (available on Amazon). It contains a lot of algae and plant matter. 

If you want to feed your plecos something healthy, Hikari Algae wafers are one of the best options.

Apart from starvation, there can also be other reasons for causing death in your pleco. For instance, your pleco is quite old and dying because of old age. (Plecos typically live 10-15 years). 

Another reason for pleco’s death can be due to any infection. For instance, some diseases like Ich can be deadly, so early detection and treatment are necessary.

Or it can also be due to the lack of oxygen in the tank. If your fish is constantly opening and closing its mouth and struggling to breathe (gasping), it indicates a lack of oxygen in the fish tank.

What To Do? So whenever you notice any death signs in your pleco, firstly detect the root cause of the issue. If it’s because of old age, there’s nothing much that you can do.

However, if it’s because of some infection, then based on the symptoms, apply the necessary treatments.

If the fish is gasping, I highly recommend adding an air stone or bubbler that creates surface agitation and thus facilitates gaseous exchange. 

And if you have a filter that creates enough water surface movement, that’s also fine. 

The goal is to ensure enough oxygen is always available in the fish tank. 

And the most important thing, ensure your pleco is fed well! Get good algae wafers for them and feed them every day or other. And also, give them treats of zucchini once a week. 

Final Thoughts

In short, if your pleco is not moving, it’s most likely exhibiting its normal behavior of staying still. However, it could also be resting, stressed, hiding, or dying. Identifying the right cause and taking the necessary action is the key. 

Unless there are any dying symptoms, there’s nothing to worry about. 

Giving a proper diet, maintaining appropriate water parameters, and providing a suitable environment to your pleco would make them thrive well.

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