Typically, plecos are going to have an easy time swimming around. They might hide sometimes, but you’ll often see them swimming around the bottom of the tank.
If you notice that one of your plecos is swimming upside down, that’s certainly something you should worry about. It’s not normal for these fish to swim in this manner.
What causes this unusual behavior in plecos, though? Does this mean that the fish is sick in some way?
Read on to discover what causes plecos to swim upside down. You’ll also learn a bit about what it takes to get the fish better.
Swim Bladder Disease
Typically, fish are only going to swim or float upside down when they’re dealing with swim bladder issues. Swim bladder disease is something that many fish experience.
This condition can be caused by a number of different things. If you see your fish swimming upside down, then it surely has some type of swim bladder problem.
The swim bladder is an organ that many fish possess. It’s a sac that inflates and deflates as it’s filled with gas.
It’s an organ that’s designed to help fish control buoyancy in water. They’re able to swim and stay upright because of this organ.
When the organ isn’t able to work properly, the fish won’t be able to swim as they normally would. It makes it far tougher for the fish to get around.
Some fish might be able to swim around a bit when experiencing some type of swim bladder malfunction. Often, fish will look as if they’re “drunk” while swimming.
A fish that has a swim bladder issue might swim upside down or it might swim sideways. Sometimes it’ll simply swim in circles and won’t be able to truly control where it’s going.
This can be a big problem for plecos since it’ll make it tough for them to eat. Also, fish with malfunctioning swim bladders might not be able to defend themselves against other fish properly.
What causes swim bladder disease? Keep reading to learn about some of the things that can cause swim bladder malfunctions.
1 – Overfeeding
Feeding the fish too much is the most common cause of swim bladder issues. You never want to feed plecos more than you’re supposed to.
If you feed the fish way too much food it’ll wind up becoming constipated. A constipated pleco will wind up having a swollen belly.
The swollen belly presses against the swim bladder and prevents it from working as intended. A swim bladder needs to be able to fill up with gas to function, but it can’t do that if it has something pressing against it.
Many people choose to feed plecos daily, but if the plecos eat algae, it’s likely that you can get away with feeding them every other day. Some plecos should absolutely be fed daily, though.
When feeding these fish, it’s best to feed them early in the morning or when it starts to get dark outside. They’re nocturnal fish that won’t be very active during the day.
It’s best to feed the fish a varied diet that will meet the right nutritional needs. Plecos eat things such as algae drops, shrimp, bloodworms, veggies, and more.
Many people give them nutritional pellets that sink to the bottom of the tank. So long as you’re being mindful of how much you feed them, it should be just fine.
If you do happen to overfeed the fish, you’ll be able to fix things. When plecos become constipated, you’ll need to take steps to clear them out.
Feed the constipated plecos frozen peas so that they will poop a lot. You’re supposed to peel the skin off first and it’s recommended to microwave the peas for thirty seconds before giving them to the fish.
Some people choose to boil the peas. Either way should work just fine.
The fish will poop a lot once it eats the peas. It’ll feel better before you know it if you feed it peas and make it poop.
Of course, it’s better not to allow the fish to become constipated in the first place. Do a better job of regulating how much food you’re giving the fish.
2 – Infections
Infections can potentially cause fish to experience swim bladder malfunctions. If a fish becomes infected, the infection might cause swelling in certain parts of the body.
Occasionally, infections might cause abdominal swelling due to the intestines becoming inflamed. This can be painful for the fish to deal with, but it’s also going to make it hard for the fish to move.
A fish might swim upside down and have a tough time getting around when it swells up due to being infected. It can be a big problem for the fish in many ways.
It’s important to understand that fish are more likely to become infected if the conditions in the tank are less than ideal. The water might be dirty because you aren’t doing water changes often enough.
Fish become stressed when the water parameters aren’t right. Stressed fish develop compromised immune systems and are more susceptible to infections.
To resolve this issue, you’ll need to clear up the infection. This involves treating the fish with antibiotics and addressing any problems in the fish tank with water parameters.
If things go well it’ll be possible to see the fish get back to normal naturally. The swim bladder issue should clear up when the swelling goes away.
3 – Worms
It’s possible for plecos to experience bloating when they get worms as well. Specifically, camallanus worms have been known to cause bloating in plecos.
When plecos get these worms, you’ll often see them sticking out of the anal areas of the fish. It can back them up and keep them from being able to poop as normal.
If the worm infestation is so bad that you can see worms coming from the anus of the fish, it’ll be necessary to take action. There are medications that can help to clear out worms and get the fish back to normal.
Failure to take action will cause the fish to keep suffering. It’ll continue to have swim bladder issues and it could even die if you don’t do something.
It’d be wise to ask the advice of an exotic veterinarian. An expert vet will be able to give you the best medication that will help the fish to get rid of the worms.
If you’re unwilling to spend money to enlist the help of a vet, you should be able to find over-the-counter options that will help. Remember that fish normally won’t get worms unless the water conditions are very bad.
You might need to address issues with water quality in the fish tank. Do what you must for the sake of the plecos.
4 – Swallowing Too Much Air
Swallowing too much air can cause fish to become bloated. When plecos are feeding near the surface, they will sometimes gulp down air.
If a fish gulps too much air, it’ll wind up experiencing bloating issues. This bloating will cause swim bladder malfunctions due to the belly pressing against the swim bladder.
This is a minor issue that should go away over time. If this is the only problem, it shouldn’t give you much reason to worry.
You won’t need to put much thought into this. It’ll be good to try to determine if any of the other causes of swim bladder issues are truly to blame, though.
5 – Physical Injuries
Physical injuries can also cause fish to have swim bladder problems. A fish might get into a fight with another fish and wind up getting injured.
If a pleco gets hit in the right spot, it could cause its swim bladder to become injured. Injuries such as this should heal over time, but they might not if the injury is severe.
Plecos have been known to injure themselves on occasion by ramming into objects in the tank. It’s possible that your fish could have bumped into a decoration and injured itself in the process.
Try to look after the fish and do what you can to help it. If it is fighting with other fish in the tank, it’ll likely be necessary to make some changes.
Never put plecos (or any other type of fish) in a community fish tank with fish that they aren’t compatible with. You must pick out compatible tank mates so that all of the fish can stay safe.
Note that male plecos don’t always get along either. Many types of male plecos will fight and hurt each other.
It might be best to keep only one male pleco in a tank. You can keep one male pleco with a small group of female plecos.
You’ll need to ensure that all of the fish have enough room. Make wise choices and your plecos will be better protected.
6 – Oxygen Problems
It’s also worth mentioning that oxygen problems will cause fish to experience strange things. Plecos need to be kept in fish tanks that have high oxygen levels.
If you allow the oxygen levels in the tank to dip too low, the fish won’t be able to breathe. What causes the oxygen levels to get low, though?
Dirty water causes the nitrate levels in the fish tank to rise. Elevated nitrate levels make it incredibly difficult for fish to breathe.
Since plecos are very sensitive to oxygen issues, they’ll be among the first fish to notice when the fish tank isn’t in good shape. It’s one reason why you must work to maintain a clean fish tank when caring for plecos.
Of course, using a good filter is a must when caring for plecos. You’ll also need to clean the tank regularly and do weekly water changes to keep things safe.
Test the water regularly and address any problems to keep the fish safe. If you don’t, you might wind up noticing the fish floating upside down.
Sometimes plecos that can’t breathe well will float near the surface of the water. They won’t necessarily be dead yet, but they’ll be struggling to try to breathe.
Hopefully, this will never happen in your fish tank. It is an extreme problem with oxygen to have, but it can occur if you don’t do a good job maintaining the tank.
7 – Dropsy
Dropsy is a condition that can cause fish to experience swelling. Specifically, it causes swelling along the abdomen.
It’s usually caused by environmental problems such as dirty water, improper water parameters, and other such issues. This is a very serious disease that can wind up killing plecos as well as other fish that get it.
The huge swollen bellies of the fish will also cause swim bladder problems. Fish might swim sideways or upside down.
Fish with dropsy will often stop eating entirely. They’ll also become incredibly lethargic.
Sometimes the scales of the fish will stand out and look unusual. Fish might even have ulcers appear on their bodies.
This condition can be treated by quarantining the fish and using aquarium salt. You’re also supposed to give sick fish antibiotics.
Fish may or may not survive when they have dropsy. It depends on the overall health of the fish, how fast you caught the disease, and other factors.
Final Thoughts
Swim bladder issues are to blame when fish are swimming upside down. The swim bladder is an important organ that allows fish to remain in control while swimming.
When the organ is malfunctioning, it’ll make them swim as if they’re drunk. Some fish can’t get around at all when they’re experiencing swim bladder issues.
This problem can be caused by constipation. Never overfeed your fish because it can lead to swim bladder problems.
It could also be caused by some type of infection or even worms. You’ll want to try to protect your fish by keeping the tank clean and safe.
Do your best to treat the fish and get it back to normal when you notice it having problems. Don’t ignore the issue because it can be very bad for the fish if swim bladder issues go on for prolonged periods of time.
If the fish has a condition such as dropsy, it might not survive. Treatment is possible, but it’s best to catch things early on.
Jeff has always enjoyed having pets, but as a child, he was drawn to his family’s fish tank. Being able to maintain a small ecosystem and observe the behaviors and interactions in the underwater world peaked his interest early on and has kept him hooked until this day. On Avid Aquarist, Jeff shares everything he’s learned about helping aquatic life survive and thrive in a home aquarium.