Cory Catfish Not Moving? Top 7 Possible Reasons!

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It’s really cool to watch the cory catfish moving at the bottom of the tank searching for food. But what if you notice that your cory catfish is not moving?

Short Answer:

The most common cause a cory catfish is not moving is its general behavior of resting in motionless state. They have the tendency of remaining still for a period of time and then beginning to forage and move around in search of food scraps.

In our cory catfish keeping experience, we often noticed our cory catfish to stay still for few moments and then again resuming their regular routine of looking for food.

So for the most part, if your cory catfish not moving but it is fine and doesn’t have any illness, you don’t need to worry anything.

That said, there can be also other variety of reasons and so read on till the end to find out more!

Pro-Tip: One of the best way to ensure your cory catfish remains happy and active is to give them high-quality food. That’s why I recommend giving your cory catfish high-quality food like this (available on Amazon).

Why is My Cory Catfish Not Moving?

Sometimes Cory Catfish just rest at the bottom of the tank; other times, it’s a sign of a more serious problem that has to be addressed. 

You shouldn’t be concerned if your fish stops moving every now and again. However, if your fish does not move for several hours or days, you should take fast steps to determine the cause and help your fish feel better. 

Your Corydoras will frequently cease moving owing to poor water quality. Although you should double-check to be sure this isn’t the issue because fish illnesses can swiftly spread across a tank.


Top 7 Possible Reasons Why Your Cory Catfish Is Not Moving

1. Your Cory Catfish is Sick or Ill

A motionless Cory Catfish might signal that your fish is unwell or ill, as your fish needs to move to stay happy and healthy. First, look for any injuries on your Cory. 

If there are no apparent signs of damage or if your Cory’s intestines are visible and look to have been chewed away, it might be affected with Columnaris illness. 

Columnaris disease is most likely caused by a scrape against the gravel or rocks in their tank and can also be transmitted through a tank and affect all fish species if not treated.

Check out this guide on Cory Catfish White Fungus Issue where I have explained more about Columnaris, its signs, and treatment.

2. Your Cory Catfish is Resting

When a cory is chased by larger tank mates or tries to hide from other fish, it will often end up at the bottom of the tank near some hiding area and not move much – likely because it is exhausted.

But then, it will usually acquire enough energy to get into that activity again after some time. So if that’s the case, try to remove the tank mate that is harassing your cory catfish.

Another reason your cory catfish could be resting is simply because it needs the resting period as part of its daily life-cycle.

Cory’s spend all day scavenging the bottom of your tank, as do many bottom-feeders. Since this can be a large and tiring task, they need to rest now and then.

3. The Water Parameters in Your Tank are Off

Corydoras are considered tropical fish. They come from waters between 72 and 82˚ F. If your Cory has been exposed to temperatures above 82˚ F, it may not seem to be eating as well as it formerly did and may not want to move about as much. 

Their bodies will be working hard, urgently attempting to cool off by releasing heat via their gills. 

You may give your Cory some rest by keeping it in a tank with colder water, below 82˚ F, and it should heal on its own over time.

If it doesn’t seem to be recuperating after two weeks in a colder tank, there’s a good possibility something else is wrong.

It’s also good to check the water parameters like pH, Ammonia, Nitrite, and Nitrate and see if they are at their recommended levels. In case you don’t have already, an aquarium water test kit like this one (available on Amazon) can be quite helpful at times.

API FRESHWATER MASTER TEST KIT 800-Test Freshwater Aquarium Water Master

4. Your Cory Catfish is Injured

If your Cory spends an unusual lot of time sitting about and not eating, you should be concerned. This might indicate that it is sick or hurt. Capture the Cory and examine it for wounds or evidence of parasites if possible.

Check your Cory’s entire body when inspecting it; they can acquire sores from scrapes against rocks or other fish, and these can be difficult to detect until they get severe enough to appear.

Read Also: Are Cory Catfish Hardy?

5. Your Cory Catfish is Unhappy or Depressed

Cory Catfish are very sociable fish, especially within their own species. While Cory Cats may survive independently, they appear to thrive in groups of two or more. 

As they roam about the tank to feed, two Cory Catfish of the same species will frequently stay near one another. This is particularly true while they are sleeping. 

If you leave your Cory Catfish to live independently and it stops swimming, it might be a sign that it is sad, lonely, or depressed. Purchase a couple more Cory’s or other calm species to make your Cory feel more at ease.

Highly Recommended: Cory Catfish Happiness Guide Every Cory Keeper Must Read!

6. Your Cory Catfish is Housed in the Wrong Environment

If you give your Cory Catfish the unsuitable tank setting, they may feel frustrated or depressed and eventually cease moving. Since Cory Catfish are bottom feeders, at least 2 inches of aquarium gravel or substrate should be present on the tank’s bottom. 

Cory Catfish tend to appreciate a tank with many live plants as well. For the fish, live aquarium plants provide shelter and hiding places. Finally, incorporate pebbles and other decorations that give opportunities for exploration.

7. Your Cory Catfish is Lacking in its Essential Nutrients

A Cory Catfish’s diet is essential to consider if your Cory stops swimming. A Cory Catfish’s diet usually consists of basic foods like fish flakes, pellets, and bottom feeder tablets. Corys will spend hours upon hours scouring the tank bottom for food. 

They’ll even dig for more by moving the surface gravel around with their jaws. While the feeding abilities of Corydoras Catfish makes them excellent tank cleaners, they should not be used as a replacement for appropriate tank maintenance.

A Cory will stop swimming and begin to swim in place if it is not given enough nourishment. To correct this, change your Cory’s meal to offer extra nutrients targeted for their individual dietary needs.

Recommended Read: Do Cory Catfish Eat Algae Wafers?

Is It Normal for Cory Catfish to Be Still?

Cory Catfish are typically quite active during the day, but they may also slumber comfortably in the same area at night. Even though Cory’s move around the tank at night, they appear to be more active during the day.

Do Cory Catfish Play Dead?

Cory Catfish are known to act dead on occasion. It’s enough to frighten any owner if they chance to be passing by their fish’s tanks at the time. But don’t worry, they’re not dead; they’re just pretending to be.

Corydoras will fake dead if they aren’t feeling well and need to hide from predators or feel threatened. It’s their strategy of avoiding being eaten or assaulted when they’re recovering from illness or stress.

Why Is My Cory Catfish Laying on The Bottom of The Tank?

It might be typical for your fish to spend a lot of time at the bottom of the tank. Catfish are bottom feeders. In addition, fish frequently sleep near the bottom of their tanks. 

If your fish’s behavior does not seem to suit either of these scenarios, and he appears exhausted and listless in the bottom of the tank, he might be sick. If you believe this is the case, you should put the fish in quarantine. 

Why is My Cory Catfish Breathing but Not Moving?

If your Cory looks immobile but still breathing, your tank most likely has an ammonia toxicity issue. Ammonia poisoning occurs when the ph level in a fish tank rises, disrupting the nitrogen cycle. Ammonia levels should be negligible in optimal water conditions. 

Tap water and the breakdown of organic stuff inside the tank, on the other hand, can both contribute to this problem. 

Even the tiniest quantity of ammonia can harm a fish’s gills, and very high quantities can be lethal. Test the water in your tank for evidence of ammonia to see whether you need to take any more steps to preserve your Cory Catfish.

Why is My Cory Catfish Lethargic and Not Eating?

There are many reasons why your fish may appear weary and sluggish. Improper water temperature is one of the most prevalent causes. Your fish will be highly passive if the water is too hot or too cold for them. 

Check your heater and make sure your aquarium is at the proper temperature. Overfeeding and poor water quality are two other probable reasons.

Related Read: The Best Aquarium Heater For 5 Gallon Tank

Why is My Cory Catfish Still and Gasping for Air at the Surface of the Tank?

Your fish will swim to the surface to breathe if there is a lack of oxygen in their tank water. Act quickly if you detect the majority of the fish gasping for breath near the surface since this is an obvious indicator of distress.

Catfish like to dwell at the top of the tank owing to oxygen shortages caused by stagnant water and high temperatures. However, owing to high ammonia concentrations or a swim bladder condition, particular catfish will inhabit the top parts, affecting the fish’s buoyancy.

If your Cory Catfish appears to be gasping for air at the top of the aquarium, it’s an indication that either your water quality is poor, or the water lacks adequate dissolved oxygen. You should test your water and think about installing a tank aerator.

I highly encourage you check out this guide on the 7 smart ways to aerate a fish tank.

What Illnesses Can Owners Look Out for in Cory Catfish?

1. Fin Rot 

Tropical fish, especially those housed in freshwater tanks, are particularly susceptible to fin rot. Fortunately, because the outward indications of this health issue are so distinct, it’s easy to recognize. Aquarium fish often have smooth or uniform margins on their fins.

Cory Fin rot causes jagged and progressively shrinking fins in catfish. 

It most commonly affects the tail, although it can also affect the dorsal, pectoral, anal, and pelvic fins. It can also occur in the presence of other health problems, such as dropsy.

If not treated as soon as possible, your Cory may perish from bacterial illness and have reduced motility and balance.

Learn More: How To Tell If Fish Fin Rot Is Healing?

2. Bacterial Infections

In aquarium fish, particularly live-bearing fish, and Cory catfish, Columnaris is a frequent bacterial illness. Its name comes from columnar-shaped bacteria that may be found in almost every aquarium setting.

Most Columnaris infections are external, manifesting as white or gray spots or patches on the head, fins, or gills. 

The lesions may show as a paler patch that lacks the usual gleam of the rest of the fish at first. The lesion may turn yellowish or brownish in appearance as it advances, and the surrounding region may become colored red.

Read Also: Why Is My Cory Catfish Turning White?


Overall, Corydoras Catfish are energetic and curious bottom dwellers who meticulously scavenge the tank bottom for food. Cory Catfish can be highly active during the day, yet they can also slumber calmly in the same area at night. Even though Cory’s move around the tank at night, they appear to be more active during the day.

As a result, if your Cory Catfish stops moving for hours or days at a time, you should examine it for symptoms of disease or damage, as well as the tank temperature and parameters.

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