Why Did My Pleco Disappear? Finding Missing Plecos

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Plecos are among the most popular fish in home aquariums. That is why so many people find that their Pleco has disappeared. After it happened to me, I investigated the issue quite extensively. To my surprise, there are many reasons for a missing Pleco. Now, I am willing to share all that I learned.

Plecos typically disappear when they go into hiding, especially during the daytime. In most cases, the hiding Pleco will emerge during the night and return to its spot once the sun comes out. However, a Pleco’s disappearance may also be secondary to an escape or when its tankmates ate the fish.

Later on in this article, I will share a few useful techniques that will help you to find your missing Pleco. I will also show you what steps you should take to prevent this from happening again in the future.

Also Read: Pleco Fish Facts

Why Is My Pleco Missing?

For some aquarists, there is nothing more unsettling than an absent Pleco. After all, these fish are large, typically growing to a size of 24 inches. More importantly, tanks are finite. Even if your Plecos hate the conditions in the aquarium, they have nowhere to go. 

With that in mind, if your Pleco has disappeared, what could be the cause? Where did it go? One of the following is most likely the culprit:

1. Your Pleco Is Hiding

A hiding Pleco should be among your first considerations. Plecos do not appreciate bare tanks. They want as many plants and decorations as you can provide. This allows them to stay hidden during the daytime. 

If you have an elaborate aquatic environment filled with pots, caves, driftwood, foliage, and the like, your Plecos have plenty of places to hide. Some fish even go underneath the substrate.[1] Plecos can remain in hiding for days, weeks, and months, only emerging for brief periods when the aquarist isn’t looking.

Also Read: Why Is My Pleco Hiding?

2. The Fish Escaped

Plecos are relatively large creatures. However, that won’t stop them from jumping out of the water, especially if you have a small tank and you did not leave a space between the top of the tank and the water level. Fish that escape a tank will most likely die. 

After all, they cannot breathe outside water. Some fish fall in the open when they jump out of the tank. These are fortunate because you can return them to the tank if you find them in time. Others fall in hidden corners where you are less likely to find them.

3. Your Pleco Is Dead

Death explains the unexpected disappearance of Plecos in two ways. First of all, Plecos like powerful currents. And if a Pleco dies, that strong current can carry its corpse to some random tank corner. It will stay there, rotting and ruining the chemistry of your water until you find it days, weeks, or even months later.

Secondly, when a fish dies, the other creatures in the tank are just as likely to eat it. Yes, Plecos are large. However, that won’t stop their tankmates from consuming them before a less observant aquarist notices their absence.

Fish are not your only concern in such situations. Because fish that die eventually sink to the bottom, mystery snails will surround these corpses and slowly but steadily eat them until nothing is left:

It is worth noting that this can also happen to live fish. A Pleco that has been weakened by disease is vulnerable to attacks from smaller fish. It is also worth noting that some Plecos are relatively small, no more than three or four inches in size, in which case a large fish can swallow them whole. 

If this happens, you won’t know what happened to the fish. With larger Plecos, you are just as likely to discover their remains in the days following their demise. Smaller Plecos simply disappear.

Also Read: Why Did My Pleco Die?

4. The Fish Was Taken Away

This sounds ridiculous, but it can happen. It isn’t commonplace for aquarists to protect their aquariums, which means that anyone can steal your fish by merely opening the lid and scooping a Pleco out.

What To Do When Your Pleco Goes Missing?

If your Pleco has disappeared, you shouldn’t be so quick to panic. Or at the very least, you should wait until you have done the following:

1. Check the Plants and Decorations

Plecos do a fantastic job of hiding, which is why you have to check every inch of your tank. Do not stop at merely pushing leaves aside and looking under ornaments. Search every object that has any sort of hollow design. 

Plecos can slip into all kinds of holes and spaces if you give them the opportunity. If possible, and if you still can’t find the Pleco, take all the decorations out. This will make it easier to find any hidden living or dead Plecos.

2. Examine the Substrate

Plecos are nocturnal creatures that spend a lot of time digging through the sandy substrate.

While some of them are too large to disappear in the substrate completely, they can submerge a significant portion of their body, and this can make it difficult for you to see them unless you search the substrate carefully.

3. Check Your Filters

Many aquarists never find their fish until the Plecos choose to emerge because it never occurs to check the filters. Depending on their size, fish can hide inside the filters or behind them. They can also hide behind submersible water heaters, though they risk severe burns in the process.

Do not limit your search to the plants, ornaments, and substrate. Fish can hide in any location that offers them protection. The smaller they are, the more difficult it will be to find them because they have more hiding options.

4. Wait For Nighttime

Because Plecos are nocturnal, they are not that active during the day. The easiest way to find them is to wait for nighttime. Once you switch the lights off, the Plecos will most likely emerge.

Please don’t wait until the daytime to search for them. Look for them once the lights are off. Otherwise, you may wake up to find that they have gone back into hiding.

5. Lure Them Out With Food

People whose Plecos are seemingly starving are encouraged to feed them at night (when other fish are sleeping), and they are most active.

You can use this same tactic to pull a Pleco out of hiding by simply adding cucumbers to the tank. The chances that the Pleco will come running are relatively high.

6. Check The Area Outside The Tank

Plecos that escape the aquarium cannot get far. Search the floor near the aquarium. Check the space between the aquarium and the nearest wall. Look for open drawers, cabinets, pots, pans, and the like in the vicinity.[2]

If you have a second tank nearby, the Pleco might have jumped from the first tank to the second one. Once you find the fish outside, start by touching it; if it is even slightly sticky or wet, return it to the tank. Do this even if it feels rigid.

If you submerge the creature, but it isn’t breathing, place it in front of a gentle water flow to flush the gills. If that doesn’t produce results, you should consider forcing water into the Pleco’s mouth using a suitable tool such as a pipette.

This process may ultimately kill timid fish that cannot handle the shock of resuscitation. This is especially true for situations in which aquarists attempt to guide the fish forward through the water like a toy to encourage breathing. But other Plecos may revive altogether.

If your Plecos survive this ordeal, put them in a separate tank until they recover. In their weakened state, they are vulnerable to attack.

They are most likely to be attacked by smaller creatures that frequent the lower sections, such as snails and other Plecos.

How To Prevent Plecos From Disappearing?

Rather than looking for your fish after they disappear, I highly suggest that you think about using the following steps to prevent them from disappearing in the first place:

1. Use a Sealed Lid

Because Plecos are known jumpers, you can keep them in the tank by adding a lid.[3] With a lid in place, the Plecos have no means of escape. Make sure that you do not leave any openings that are large enough for your Plecos to fit. 

The creatures will use any opportunity you give them to escape. It would help if you also left a space between the top of the tank and the water level. If the tank is filled to the brim, it will facilitate Pleco’s escape.

2. Adjust The Water Parameters

I highly suggest that you avoid the poor conditions in the water that compel fish to jump. Plecos require specific parameters to remain healthy. That includes a pH of 7.0 to 8.0 and a temperature of 74 to 80 degrees F.[4]

They want relatively soft, highly oxygenated water with a strong flow and a 50 to 100 gallons tank. If the tank’s conditions are low, the Pleco will look for a way to escape the discomfort. If it can’t jump out of the tank, it will hide.

To ensure that your water conditions are adjusted, I highly suggest getting the API Aquarium Test Kit (link to Amazon).

That bundle will quickly measure your pH, ammonia, nitrates, and nitrites. It also comes with a stripe that indicates when one of these parameters is out of range.

If the temperature in your tank isn’t stable, I suggest getting a new heater. Low-quality devices will cause fluctuations, which will dramatically stress your fish and compromise their general state. I personally use the Cobalt Aquatics Neo-Therm Pro Aquarium Heater (link to Amazon).

Also Read: Plecos Water Parameters

3. Conduct Regular Water Changes

I highly recommend carrying out a 20 percent water change once or twice a month. This will prevent the concentration of ammonia and other toxins from growing. You can also use water conditioners to neutralize ammonia, chlorine, and chloramine. 

A regular water change will keep the water clean, protecting the Pleco from diseases and distress that would typically lead to hiding and jumping.

Also, don’t forget to vacuum the substrate. The substrate houses waste and leftovers that will rot in due time, corrupting the water in the process.

4. Add A Small Amount Of Vegetation

Remember that you shouldn’t respond to a hiding Pleco by removing the plants and ornaments since a bare tank will induce stress in Plecos.

Stressed fish are more likely to fall sick, at which point they will fall prey to aggressive tankmates, or they will simply die, and those tankmates will eat them all the same.

Add a suitable amount of foliage and ornaments. Their presence will alleviate Plecos’ stress, improve their physical and mental health, and make them less likely to jump.

They might hide behind the foliage, you add, but they are less likely to do so when they feel comfortable.

Also Read: Plants Plecos Love

5. Choose the Appropriate Tankmates

Place your Plecos in tanks with compatible tankmates like Arowanas, Danios, Pencil Fish, and Hoplo Catfish that are less likely to attack and eat the Pleco.[5]

But if the Pleco dies, you should remove it from the water immediately. Please do not leave it in the aquarium, even if the other fish are eating the remains. The carcass will ruin your water before the other fish can consume the whole thing.

Also Read: Pleco Fish Tank Mates

6. Consider the Pleco’s Personality

Some Plecos love to hide. This makes them an inconvenience because people buy fish for the express purpose of looking at them.

But if your Plecos appear healthy in those few moments when you see them, you have no reason to lure them out of hiding.

They most likely emerge at night when you and the other fish have gone to bed. This behavior is perfectly normal for Plecos.

Is it Normal for Plecos to Hide?

It is normal for Plecos to hide. Since they are nocturnal, Plecos prefer to hide during the daytime and will come out at night.

Some Plecos are social and will mingle with their tank mates during the day. But if your Pleco prefers to hide, there is very little you can do to change its personality.


If you can’t find your Pleco, you should first look outside the tank. That is especially true for tanks that don’t feature a lid or when there is a significant gap between the lid and the tank’s walls. If it’s not outside, the Pleco is somewhere within the tank.

Check the filters, heater, substrate, and decorations. Plecos are experts when it comes to hiding and are most likely to go outside during nighttime.

Either way, I suggest that you ensure that the water parameters are suitable for that particular fish. That is because stressed Plecos are more likely to hide.


  1. https://www.thesprucepets.com/missing-aquarium-fish-1381216
  2. https://www.practicalfishkeeping.co.uk/fishkeeping-answers/where-did-these-fish-disappear-to/
  3. https://www.keepingtropicalfish.co.uk/fish-database/common-pleco/
  4. https://www.aqueon.com/information/care-sheets/plecostomus
  5. https://www.buildyouraquarium.com/plecostomus-tank-mates/