Fish, Tanks and Ponds

Fish, Tanks and Ponds
A comprehensive guide to fish

Goldfish buoyancy problems

Floating Ryukin


Some of the fancy goldfish varieties are well known for suffering from buoyancy problems from time to time. Quit often this condition is referred to as a swim bladder problem and in most cases this isn't so.

Some of the extreme round bodied goldfish can and do suffer from a malformed or displaced swim bladder and it can lead to the fish being unable to maintain neutral buoyancy or even unable to maintain it's equilibrium. In such cases the problem will be apparent right from birth and the fry exhibiting this would normally be culled.

Most of the time what is referred to as being a swim bladder problem is a floatation problem and there are a few potential causes for this.


One of the most common causes of fancy goldfish having a buoyancy problem is digestion problems caused through:

  • Poor diet or poor feeding,
  • Bacterial disease.
  • Kept in water which is to deep.
  • Poor breeding.
  • Air trapped inside the fish.
  • Injury through poor handling.


The symptoms can vary but usually it is one of three options. Some fish float like a cork and have to fight to get below the surface. Others sink like a stone and it is an effort to swim and finally some fish lose their equilibrium and struggle to keep the right way up.

Fish which sink don't have to much of a problem with coping, Fish at the surface will tire themselves by trying to swim downwards.

Upside down fish do least well and if the fish doesn't look like recovering then euthanasia should be considered to end unnecessary suffering because such a fish would not be able to feed at all and if floating it may expose its underside to the air where it will dry and become a source of infection and pain to the fish.


The different causes need treating differently. If the cause is due to a malformed swim bladder which is quite common in the round bodied fancy goldfish due to the modified body shape which means that internal organs have been displaced to some degree. Then nothing can be done to put this right. Some fish cope quite well with the condition and as long as they are protected from being bullied they will be fine depending on the severity of the condition.

If it is caused through a digestive problem due to poor diet or poor feeding then treatment is simple and straight forward. Add one level teaspoon of Epsom salts per 18 litres of water. This will act as a laxative and the fish normally recovers within a day or two. Increase the amount of fibre in the fish's diet, prevent temperature fluctuations and don't feed the fish at the surface with dried food or the condition may keep recurring.

Injury, if injury is the cause keep the fish in a very shallow bowl where the water is just enough to cover the fish. This will prevent the fish from working its swim bladder and if kept rested for a week to ten days then the fish has a chance to make a rocovery.

Finally if the cause is through an infection, this is in fact very rare. There is a viral disease which affects cold water fish when the temperature falls below 50F. The disease is confined to the carp family and a few other cyprinids. The symptoms for this disease are:

  • Darkened colour.
  • Prolapse.
  • Haemorrhages both internally and externally.
  • Shallow breathing.
  • Loss of balance.

As mentioned this is unlikely to affect fish in a tank, this condition, especially in fancy goldfish is rarely caused by disease.


This condition is easy to prevent if you follow a few simple guide lines.

  • Avoid fluctuations in temperature, this plays havoc with a fish's digestion.
  • Don't over use dried food, use lots of high fibre food in their diet such as processed peas with their skin removed, blanched spinach, nori, algae, blanched lettuce. wholemeal bred, daphnia and blood worms.
  • Don't feed at the surface, if the fish gulps in air when it is feeding then some of that air may be swallowed and might cause this problem.
  • Don't keep fancy goldfish in deep water, their swim bladders are quite inefficient and if they have to work to hard they may not cope.
  • Avoid injury. Sounds simple but how many of you buy a new fish, Take it home, Float the bag containing the fish for 20 to 30 minutes and then puncture the bag with your thumb in order to make a hole so that you can easily tear the bag open? We've probably all done it at some point if we're honest. But doing this greatly increases the pressure in the bag and then releases it very suddenly. Doing this can be very damaging to a delicate organ like a swim bladder.