The number of people keeping a cory catfish in their aquarium is always increasing due to there being such a variety of different cory types with different sizes, patterns and colors as well as how great they are as members of your tanks clean up crew, we only expect their popularity to keep growing.
Some types of cory catfish are easy to care for where as others are usually better for people with some prior experience within the fish keeping hobby but generally, they are a low maintenance fish to have in your tank.
That said though, in some cases, you may end up having problems with your pet cory catfish laying on its side and we see a couple of people reaching out for help with this each month.
Due to this, we have chosen to publish this article, going over the more common causes of a cory catfish laying on its side as well as how to fix the problems.
Our hope is that we are going to be able to help as many of our readers as possible help their cory catfish get better as quickly as possible.
Is It Normal For A Cory Catfish To Lay On Its Side?
As we covered in our article going over dealing with a bloated cory catfish, it is not normal or natural for a cory catfish to have issues maintaining its normal swimming posture.
If your cory catfish is laying on its side then it is almost always an early warning sign of a potential problem either in the aquarium or with the fish that has to be treated as quickly as possible.
What Causes A Cory Catfish To Lay On Its Side?
The most common reason that your cory catfish will be laying on its side is due to the fish having swim bladder disease.
In addition to swim bladder disease, there are also another nine less common reasons that your cory catfish will lay on its side that we will cover below too.
Swim Bladder Disease!
The swim bladder is an internal gas-filled sac that allows fish to maintain their position in the water column as well as giving them the ability to make sudden changes in direction or speed when they need too.
In cory catfish, the swim bladder is especially important as it gives them the ability to rest on the substrate of your aquarium without being pulled to the surface by the water.
The most common symptom of swim bladder disease in cory catfish is the fish being unable to maintain its normal swimming posture and instead floating upside down or laying on its side at the bottom of the tank.
Other symptoms of swim bladder disease include a cory catfish being bloated, irregular swimming patterns and surface gulping but these are much less common in corys than other fish species.
The most common cause of swim bladder disease is cory catfish being fed the wrong diet and eating too much air when they are feeding.
This is especially common in corys that are kept in aquariums with a lot of décor or plants as they can have a hard time getting to their food and end up taking in more air than normal.
You can treat swim bladder disease in your cory catfish by making sure that you are feeding them a high-quality diet that is designed for bottom-dwelling fish like corys as well as making sure that they are not overfeeding.
In most cases, this will be enough to fix the problem but if your cory catfish is still having issues after changing its diet then you may need to consider using medication.
The most common medications used to treat swim bladder disease are anti-parasitic drugs like metronidazole but you should always speak to your veterinarian before using any medications on your fish.
Stress Or Anxiety!
While it may seem like a cory catfish would not be stressed or anxious due to how hardy they are, this is actually one of the most common causes of a cory laying on its side.
Corys are very sensitive to changes in their environment and even something as small as a new piece of décor being added to the tank can cause them stress.
In addition, corys are also very sensitive to changes in water parameters like temperature and pH and even a slight change can cause them stress.
Common symptoms of stress in a cory catfish include the fish laying on its side, listlessness, and a loss of appetite.
If you think that your cory catfish is stressed then the best thing that you can do is to try and identify what is causing the stress and remove it if possible.
In most cases, this will be enough to fix the problem but if your cory is still stressed then you may need to consider using medication.
While cory catfish are not known for being particularly greedy fish, they can still over eat if they are given the opportunity.
If your cory catfish is overeating then it can lead to issues with excess gas in the digest system of your cory catfish that will end up having a similar effect to swim bladder disease that we covered earlier including the cory laying on its side.
In fact, overfeeding can end up causing swim bladder disease with excessive overfeeding often being enough to drastically increase the chances of your cory catfish developing swim bladder disease.
Rolling In The Water Flow!
If the water flow levels in your tank are too high for your cory catfish to swim in then it may just relax and let itself roll in the water flow with it potentially seeming as though the fish is laying on its side.
It is usually simple to workout if your cory catfish is just rolling in the water flow as the fish will roll at a steady pace, back and forth, over and over without having to move its fins or tail.
This is an obvious indication that you need to reduce the water flow in your tank or investigate any serious issues in your cory catfish to cause it to be able to maintain its normal swimming posture.
The Fish May Be Resting!
While cory catfish may seem to be a particularly lazy fish, they do still need to rest and may just be taking a nap when you see them lying on their side.
If your cory catfish is laying on its side just to rest then it will usually only be in this position for a couple of hours before going about its business as normal again.
Ammonia And Nitrate Levels!
If the ammonia or nitrate levels in your cory catfish tank are too high then it can lead to your cory catfish becoming sick which may result in the cory laying on its side.
This is rarer than some of the other common issues that can cause a cory catfish laying on its side though but it is worth checking the ammonia and nitrate levels in your tank if you have a water test kit handy.
Your Cory Is Injured!
If your cory catfish has been injured, for example, by being nipped by another fish then it may lay on its side as a result.
This is particularly common in corys that have been injured around the abdomen area as this can cause swim bladder disease which we already covered earlier.
Other injuries can also lead to your cory catfish laying on its side due to problems with its muscles, ligements, fins, tails, and internal organs making it difficult for the cory to stay upright.
While constipation is not a common issue in cory catfish, it can still happen from time to time and when it does, you may notice your cory catfish laying on its side.
This is because the cory catfish is having difficulty passing waste and the extra weight makes it difficult for the cory to stay upright.
If you think that your cory catfish may be constipated then you can try feeding it a high-quality diet as well as giving it plenty of live foods such as brine shrimp to help keep things moving along smoothly.
Aggression From Tank Mates!
Constant aggression from the tank mates of your cory catfish can not only result in injury as covered above but it can also spike the stress and anxiety in your fish as covered above too.
This just compounds the two together and can quickly cause a number of issues in your cory catfish and in some cases the cory may just lay on its side.
Dropsy is a very serious issue that can affect cory catfish as well as a number of other fish species.
Dropsy is where the cory catfish’s scales start to protrude outwards and the cory’s body starts to swell up.
This is usually a sign of a bacterial infection or disease and if not treated quickly enough it can be fatal.
The swelling from dropys can cause your cory catfish to really struggle to swim and it will commonly just lay in the water be it upside down or on its side.
Summary Of Your Cory Catfish Laying On Its Back!
Here is a quick summary of the more common reasons that your cory catfish may end up laying on its side:-
- Swim Bladder Disease!
- Stress Or Anxiety!
- Rolling In The Water Flow!
- The Fish May Be Resting!
- Ammonia And Nitrate Levels!
- Aggression From Tank Mates!