Swim bladder disease: Is your fish swimming upside down?

Swim bladder disease is one of the most common problems affecting goldfish. If you’ve seen your fish swimming upside down, or on its side, then you’ve seen a swim bladder problem.

Although often called a “disease”, it is actually a symptom that can have a number of different causes. There is not one specific “disease” that is the cause of all swim bladder problems in goldfish.

Proper goldfish care can prevent most swim bladder problems.

As it is not actually a disease, swim bladder problems are not contagious. If one fish has a problem, your other fish won’t “catch it”. However, they may still be at risk of developing similar problems.

Fortunately, swim bladder problems can usually be cured fairly easily, as long as you spot them early enough.

If you see your fish swimming upside or on its side, act quickly!

There are several good swim bladder treatments available. But, before you try to cure your fish, read on to find out more about treating swim bladder problems.

What is swim bladder disease?

Swim bladder disease is when a fish loses its ability to regulate the air going in and out of its swim bladder. This causes the fish to swim strangely, on its side, or even upside down.

The job of the swim bladder is to help the goldfish stay stable in the water and control the way in which it floats.

If the goldfish wants to swim upwards, towards the top of the tank, then it will take air into its swim bladder. This makes the goldfish more buoyant (like an inflatable in a swimming pool) and it rises towards the surface.

If the goldfish then wants to swim downwards, towards the bottom of the tank, it will release air from the swim bladder. You may see this air coming out of the fish’s mouth in the form of bubbles as it swims to a lower point in the tank.

Why Is My Fish Swimming Upside Down?

If your fish is swimming upside down, it has a problem with its swim bladder.

Your fish has stopped being able to control its swim bladder and has got stuck with too much air inside it.

The reason for this could be constipation, a poor diet, eating habits, or an infection.

Causes of swim bladder disease

Causes of swim bladder problems include:

  • Constipation, which results in excess food pressing against the swim bladder. This is a common problem in goldfish, which you can read about here.
  • Swallowing air at the surface of the tank when eating
  • Eating the wrong kinds of food, which then ferment in the gut
  • Sudden changes in temperature
  • Bacterial infection
  • Parasitic infection

Fancy goldfish often suffer from deformed swim bladders, as they have been bred to have such unusual body shapes.

Treating the problem in 5 easy steps

Swim bladder problems can be very serious. But there is hope! It is also one of the most straightforward issues to treat.

Follow these 5 simple steps:

  1. Test the water quality and temperature using a test kit. Is the tank properly cycled? Do you do regular water changes? Is there ammonia or nitrite in the water? Is the temperature stable? If not, you need to urgently take action to improve and stabilise your water parameters.
  2. Do not feed the fish for at least 48 hours. Don’t worry – goldfish really don’t need to eat much!
  3. After 48 hours, start to feed the fish very small amounts of peas with the shells removed.
  4. Add some aquarium salt (one teaspoon per gallon) to de-stress the fish. You can buy aquarium salt online or at pet stores.
  5. Try a specific swim bladder treatment.
  6. Try a treatment for bacterial infection such as API Melafix.

You should soon see your goldfish start to swim in a more stable, upright position.

Stopping it happening again

After your fish has recovered from swim bladder disease, you should consider making changes to their diet.

Here are 5 top tips to prevent swim bladder problems.

  • Read our article on feeding goldfish and feed a varied diet to your fish.
  • Feed sinking pellets instead of flakes. You can find out more about pellets in our guide to feeding pellets to your goldfish.
  • Feed your goldfish peas with the shells removed, boiled vegetables, bloodworms and brine shrimp.
  • Soak food in tank water for a few seconds before adding to the tank. This will make sure it sinks and stop your goldfish gulping air at the surface.
  • Feed less regularly. Goldfish really don’t need to eat much at all. There is much more risk of over-feeding your goldfish than there is of under-feeding them.

15 thoughts on “Swim bladder disease: Is your fish swimming upside down?”

  1. My black moor has been bullied and harassed by my fancy orando goldfish which has resulted in me removing the Moor. He became exhausted. He also started swimming on his side
    Since putting him in a separate tank ..I think it seems he has swim bladder. Ive witnessed him swimming along the bottom on his side, struggling to stay straight and volant and for the past two days hes just at the bottom of the tank. When I enter the room he wiggles a but but then looks as if he’s just going back to sleep.
    Hes fins look fine no signs of rot.
    I changed the water yesterday and introduced more if the original fish tank water in to his hospital tank.
    But am so worried. I think he must be suffering.
    If its swimbladder I will fast him for 3 days and introduce some shelled peas.
    Do I also need salts…or a commercial medicine.
    Its so stressful to see them struggle.
    Ive had him about 9 months no problems

    • Did your fish recover? Because i have a black more and he is doing that exact same thing like exactly the same. If you’re fish did recover what did you do to help it? Thanks so much

      • Did any of your black moor recover because we have two but one of them is doing the exact same thing and we separated him from the others because they would push him around but I really feel so sad for him and want him to be back well any options or anything

        • does anyone here had their fish recovered? mine i just laying on its side the whole time, and swims in circles while sinking. i did fasting, increase the temperature and the water is okay.

  2. One of my goldfish which are Shubenko species (a Japanese variety, I think), developed swim bladder problems. I followed some advice and did partial water changes each day for a couple of days to make sure the water was cool enough ( it is humid where I live) and to remove excess nitrogen. I then added the prescribed amount of tropical conditioning salts to my tank (to cover the whole volume of water in it) and then with each partial water change since, I’ve added the right dose to the new amount of water. At that time I also fasted the fish for 48 hrs then started feeding them 1/2 a pea a day each. Within a few days the affected fish’s buoyancy improved although 3 to 4 weeks later it is still experiencing some problems, it’s swimming has improved a lot and they are still on the pea diet. I’m going to introduce sinking pellets to them or maybe live food like brine shrimp so they don’t gulp in air at the surface while feeding. Hopefully the fish will continue to improve but I will keep checking on his behaviour daily. Hope your fish get better. Gabrielle

  3. I have a pond of shubunkins and 2 of them have started acting funny; one of them hardly swims and mostly just lays near the bottom of the pond with his face downward and his body slanted upward but just a few days ago he was swimming upside down and laying upside down, the second fish swims perfectly fine but rests near the bottom a decent amount just like the other fish (head down and body slanted upward) are these also signs of swim bladder?? I’m not quite sure…

  4. My little comet just started swimming funny last night not really swimming much and being on the bottom of the tank, today and tonight it’s laying on its side on the bottom I put it in a bowl instead of the big tank with the my 4 other goldfish we’ve had the comet about a year and a half what can should I do?

  5. hello,
    i have a pair of fancy goldfish in a 23 gallon tank and at some point last night one got his fin stuck in the filter vent, it’s not damaged when we got him out of it but he is swimming on his side and upside down. I turned the light off, added a bit of aquarium salt to help him not stress out, but it’s been a few hours and he’s still not upright totally. Is there anything else I can do or do I just need to wait a while longer?
    I will add that he is quite old, a little more than five years, and he’s never had issues before other than little scratches and stuff like that.

  6. i have had my goldfish for nearly five years and it has been swimming on its side for about twenty or three weeks i have tried everything from cleaning my tank to changing its eating habits, i have got a new filter , i have tried the pea thing and nothing seems to be working, i don’t know what else to do, can you please advise me what i can do to fix this ? thank you


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