Home | Aquarium Livestock | “My Fish is Floating” – Swim Bladder Disease in Goldfish and Others

“My Fish is Floating” – Swim Bladder Disease in Goldfish and Others

Most goldfish owners have encountered fish that suddenly become unable to submerge.  Try as they might, they float, often belly-up, at the surface, and seem to be in great distress.  Less often, the hapless victims may be unable to rise to the surface, or may swim in an “off balanced” or head-down position.  Fantails, Orandas and other strains with rounded bodies are the most common victims, but Comets and others are not immune.  The problem is also frequently seen in Bettas, or Fighting Fishes, but may afflict any species.  Swim Bladder Disease almost always involved.  This condition is actually a general term applied to a wide variety of ailments, rather than a specific disease per se.  Today we’ll look at its causes, prevention and treatment.

Fish with Swim Bladder Disease

Uploaded to Wikipedia Commons by Humanfeather / Michelle Jo

The Swim Bladder

The swim bladder is a sac-like organ located in the abdomen of most bony fishes, but is absent in the cartilaginous fishes (sharks, rays and their relatives).  The lining of the swim bladder, and the many blood vessels that transverse it, allow gasses to be passed into and out of the organ.  Goldfishes and certain others are also able to exchange gasses through a duct or opening in the bladder that leads to the esophagus.  In this manner, fishes control their buoyancy, or ability to float and move up and down in the water column.

Swim Bladder Disease

In general terms, Swim Bladder Disease can be described as a malfunctioning of the swim bladder.  Victims typically struggle at the surface but cannot submerge, but others sink to the bottom or swim in an odd manner, as described earlier.  A wide variety of causes have been identified.


Causes of Buoyancy and Swimming Problems

Red Cap Oranda

Uploaded to Wikipedia Commons by Adityamadhav83


Swim Bladder Disease most often arises when pressure is brought to bear on the bladder.  The pressure itself may be caused by a variety of conditions, such as over-eating, a blockage in the digestive tract (inability to pass wastes), a tumor, cyst or other growth, retained eggs or young, or a physical injury.  Once the bladder in compressed, gasses may be trapped within, unable to enter, or both.


Somewhat related to over-eating is the use of dry fish foods such as flakes and pellets.  If these foods are gulped down quickly, before they have absorbed much water, they may swell within the digestive tract and put pressure on the swim bladder.  Low water temperatures can exacerbate the problem by slowing digestion.

Bacterial and Viral Infections

During my years working at the Bronx Zoo, aquatic amphibians were sometimes rendered unable to submerge.  In nearly all cases, gasses produced by bacterial infections were at the root of the problem.  I do not believe this has been documented in fishes, but it may be worth considering.  Viral diseases that disrupt diffusion through the bladder’s lining have also been implicated in Swim Bladder Disease.

Ryukin Goldfish

Uploaded to Wikipedia Commons by Lerdsuwa

Body Shape

Orandas and similarly-shaped goldfishes seem prone to Swim Bladder problems due to the configuration of their bodies.  Selective breeding for a rounded body has likely changed how the organs are situated, and how close they are to one another (when compared to, for example, a comet goldfish).  Pressure builds up quickly when anything is amiss within the body.


Keeping your fishes at the proper temperature and pH (considering the species) and maintaining excellent water quality will strengthen the immune system and enable them to fight off many of the causes of Swim Bladder Disease.  Water testing kits are essential for all fish keepers, including those with goldfishes and bettas.  Please post below if you need specific information on the needs of the fishes that you keep.

Pre-soaking of pellets and flakes has been suggested as a means of avoiding the swelling issue discussed earlier.

Treating Swim Bladder Disease

Bacterial or viral infections should be treated with appropriate medications.  Please post below for further information.

If an impaction is suspected (i.e. if no waste products have been passed), try withholding food for 3-4 days.  Depending upon age and species, this will not harm your fishes…some can even handle week-long fasts.  Be sure that the temperature is correct for your species, and then slowly raise it a degree or two, while remaining within the safe range, in order to speed digestion.

Lowering the water level may limit struggling and assist those that need to surface for air.

Removal of gasses via aspiration of the swim bladder is possible, but should only be done by a veterinarian or other trained professional.  Please see the article linked below for information on a related procedure to remove gasses from seahorse pouches.  I’ve worked with zoo and aquarium veterinarians who have operated on the swim bladders of large fishes, but I’m not certain if such is ever done in private practice.  Please post below if you would like further information.

Some aquarists recommend the use of skinned frozen peas.  The peas are lightly steamed or micro-waved for 20 seconds, and then fed to ailing fish.  A 2-3 day fast prior to the feeding may be useful.  Rapid cures have been claimed, although details as to the mechanics of the process are not clear.

Please check out my posts on Twitter and Facebook.   Each day, I highlight breaking research, conservation news and interesting stories concerning just about every type of animal imaginable. 


Further Reading

Seahorse and Pipefish Health: Gas in Pouch

Koi at the Brooklyn Botanical Gardens



  1. avatar

    Thank you so very much for the informative article. When I used to have Ryunkin, a few of them would get “the floaties” after feeding time. I had found that if I soaked the dry pellet feed prior to a feeding, this also helped prevent some swim bladder issues. I would take a shot glass of water out of the tank, put the pellets in the glass, and wait until the pellets became saturated and swelled before putting them in the tank. The fish wouldn’t be able to gorge on tiny pellets, and instead ate fewer pellets at a slower rate, and thus wouldn’t get digestion related swim-bladder problems as frequently.

  2. avatar

    Hello Nicole,

    Thanks for the kind words and interesting observation; other readers appreciate hearing first hand experiences (other than my own!) as well. There seems to be quite a bit of variation in the time frame among different strains and species…when you have time, please let me know how long, on average, it took before the fish began to float. Thanks, best, Frank

  3. avatar

    It kind of sucks because a lot of aquarists arent educated on this ‘Buoyancy’ topic. If you get on forums online, you will see this issue of fish floating upside down or on their side and SO MANY people just comment and say that your fish is dying and to “put it down humanely”… I can’t stand this when this happens. It’s like I can’t leave enough comments to make up for mis-education and research. This is truly an educational piece you wrote and I will most likely just share this article instead of wasting 30 minutes of my time describing the issue like I have been doing.

  4. avatar

    Hi maggie,

    Thanks for your concern and the kind words. I know what you mean, as I also answer questions concerning reptiles, birds and other animals…Internet info is a mixed bag – sometimes it’s best to just pick and choose carefully, as you mention, since there’s no way to keep up with all that is printed on any topic. Please let me know if you need anything, and thanks very much for sharing my articles, best, Frank

  5. avatar

    Glad I found this site. This is a totally informative article and I definitely got something out of it today. I wonder how many vet actually perform aspiration of the swim bladder.

  6. avatar

    I bought two goldfishes last months but both died one by one I kept them with mollies and betta don’t know what was the reason behind it CAn you guide me about it please

  7. avatar

    Hello Fish Aquarium, We would need a great deal more information about the tank to help you figure out what might have happen. The tank size, size of the fish, number of fish you tried to keep them with, the age of the tank and how you added the fish, and water test results for at least Ammonia, Nitrite, Nitrate and pH would be helpful. Generally speaking, it isn’t recommended to keep coldwater fish like goldfish with tropical fish like mollies, and bettas are best kept alone. Goldfish do better at lower temperatures than tropical fish like mollies and bettas, and goldfish are also very “dirty” fish that produce very high levels of Ammonia in their waste that can be dangerous to themselves and other fish if the tank is too small or doesn’t have enough filtration. If you would like to speak with someone about your tank in more detail, you can reach our staff at 717-299-5691.

  8. avatar

    I have an oranda and a Ryukin that both have swim bladder I believe. The Ryukin mostly sits on the bottom but will swim around for a bit then get right back to the bottom. The oranda is floating upside down and keeps trying desperately to right itself and swim it’s belly is all red. Neither of them we’ll eat. I tried feeding the shelled peas but again they will not eat them. I am so upset I love my fish I have no idea what else to do. My water parameters are great. They both were living in a 75 gallon tank but my pleco who had never bothered them before started sucking and chewing on mostly the oranda. He ended up destroying his tail fin and belly fin. I took them out and now have them in a 10 gallon tank until I can get a bigger one. I clean it once a week removing 25%. Any advice would be greatly appreciated.

  9. avatar

    Hello Lisa, Those symptoms seem like something environmental to me. When was the last time you tested the water parameters, and what are the most recent actual values, especially for pH, Ammonia, Nitrite, Nitrate and temperature to start with? Other than the shelled peas, what have you been feeding them? Is there anything in the original tank other than the pleco and the 2 goldfish? What type of filtration do you have on both tanks?

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About Frank Indiviglio

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Being born with a deep interest in animals might seem unfortunate for a native Bronxite , but my family encouraged my interest and the menagerie that sprung from it. Jobs with pet stores and importers had me caring for a fantastic assortment of reptiles and amphibians. After a detour as a lawyer, I was hired as a Bronx Zoo animal keeper and was soon caring for gharials, goliath frogs, king cobras and everything in-between. Research has taken me in pursuit of anacondas, Orinoco crocodiles and other animals in locales ranging from Venezuela’s llanos to Tortuguero’s beaches. Now, after 20+ years with the Bronx Zoo, I am a consultant for several zoos and museums. I have spent time in Japan, and often exchange ideas with zoologists there. I have written books on salamanders, geckos and other “herps”, discussed reptile-keeping on television and presented papers at conferences. A Master’s Degree in biology has led to teaching opportunities. My work puts me in contact with thousands of hobbyists keeping an array of pets. Without fail, I have learned much from them and hope, dear readers, that you will be generous in sharing your thoughts on this blog and web site. For a complete biography of my experience click here.