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SWIMBLADDER MALFUNCTION   

   The swimbladder is an important feature found in the vast majority of fish. It is basically a gas filled sac that serves the function of maintaining the fish's position in the water, in other words it keeps it neutrally buoyant so that it does not sink or float. Fish are able to release air from the swimbladder when they need to rise, or fill it when they need to sink. The swimbladder is always maintained at the same size due to the effects of pressure on the gas inside it. For instance, the higher in the water column the fish is, the less pressure there is on the swimbladder. As a fish rises the decreasing pressure causes the gas inside the swimbladder to expand. In order to keep the swimbladder the same size the fish therefore releases excess gas during its ascent. By keeping the swimbladder the same size the fish is able to maintain its position in the water column whilst using very little energy.
Fancy goldfish take in and expel air from their swimbladders via a tube (called the pneumatic duct) connected to the gut. This, coupled with the more extreme body shapes found in some varieties, contributes to the occurrence of swimbladder problems in these fish. Although swimbladder problems can occur in most species, it is fancy goldfish in which they most commonly occur.

SYMPTOMS:

A malfunctioning swimbladder is characterised by the inability of the fish to hold its position in the water. They may float upside down at the surface or on the base of the tank, or simply spend most of their time floating around the tank helplessly with occasional bursts of vigorous swimming.

CAUSES:

There is a multitude of potential causes of swimbladder malfunction, and a process of elimination will usually determine whether or not the condition will be treatable. The following are potential causes of swimbladder malfunction in fancy goldfish.

         Infection:Viral, bacterial and parasitic infections can potentially affect the swimbladder causing it to cease working properly. Although rare, certain parasitic worms and protozoa (single celled parasites) may potentially block the pneumatic duct preventing efficient gas exchange.

  • Feeding Poor Quality Foods:The unusual body shape of some fancy goldfish can lead to problems occurring after they have been fed. Poorly digested foods tend to sit in the intestine and expand. This may then cause the gut to expand and put pressure on the swimbladder and the pneumatic gut. This results in gas exchange being impeded until the food has passed through the gut. Dry and dusty diets can also directly clog the pneumatic duct, preventing gas exchange. A good quality flake food, such as TetraFin or TetraMin, is therefore important.
  • Excessive Air Inhalation:When fancy goldfish feed from the surface, they may take in air which can expand the gut; causing pressure to be put on the swimbladder.
  • Overfeeding:If the fish is fed too much then this will also cause the gut to expand, putting pressure on the swimbladder and impeding its function. This is a particular problem in colder water, where the metabolism of the fish is lower and its ability to process food is reduced.
  • Constipation:Caused by the feeding of the wrong type of food, it results in a build up in the gut and subsequently pressure being put on the swimbladder.
  • Internal Growths:Tumours and other abnormal growths inside the fish may put pressure on the swimbladder, preventing its normal function.
  • Dropsy:The build up of fluid inside a fish results in the condition known as dropsy. This is often associated with internal diseases and is characterised by the fish swelling up. This build up of fluid can also put excessive pressure on the swimbladder.
  • Rapid Changes in Temperature:The metabolism of fish is determined by their surrounding temperature, and therefore so is the rate at which they can digest food. If the temperature suddenly drops then food may remain undigested in the gut for longer periods, building up and putting undue pressure on the swimbladder.
  • Age/Size Related:With some of the more extreme varieties of fancy goldfish, in particular the round bodied types, their shape causes the internal organs to be closely bunched together. As the fish grows this may become gradually worse, eventually causing permanent pressure to be exerted on the swimbladder.

PREVENTION:

By examining the causes mentioned above there are some steps that become apparent through which swimbladder malfunction might be avoided in fancy goldfish. Firstly, they should be fed on a highly digestible, good quality flake food such as TetraFin, in order to reduce the likelihood of it building up in the gut. Feeding should be limited to two to three small meals a day, only feeding as much as the fish will consume within a few minutes. The amount of food offered may need to be reduced if the temperature in the tank drops. Every couple of days fancy goldfish should also be fed on Tetra FreshDelica treat foods, as their high roughage and water content will facilitate digestion and help to reduce the likelihood of the gut becoming clogged. Excessive changes in water temperature should also be avoided, for instance, make sure the tank does not get too cold at night.
TREATMENT:

If, despite taking precautions, your goldfish does develop a swimbladder problem it is important to determine what the likely cause is. If the problem tends to occur after feeding then it is likely to be linked in some way to it, whilst if it is permanent then it could either be an internal infection or growth, or be due to the arrangement of the internal organs. Depending on the cause the problem may or may not be treatable. As it is often impossible to definitely identify a particular cause for swimbladder problems, it is worth following a set treatment protocol whenever they arise.

  • Check water quality and the cleanliness of the gravel. Take appropriate action if they are unsuitable.
  • Check the temperature of the tank and ensure that it is not fluctuating, especially at night when the room may get cold.
  • Cease feeding for three days or more to allow the gut to clear. In extreme cases of constipation adding Epsom salts to the tank may be effective. These should be dissolved in a small volume of water and added to the aquarium at a rate of 2.5g per 18litres.
  • If possible raise the temperature of the tank by 5 degrees, over the course of a few days. This will speed up the passage of food through the gut.
  • Administer a general treatment, such as TetraMedica General Tonic, in case an infection is present.
  • Add aquarium salt at a rate of 3grams per litre. This can reduce stress and relieve pressure caused by fluid build up.
  • Resume feeding with a good quality food, such as TetraFin, and offer Tetra FreshDelica at least once a day to start with. Feed two times a day, only feeding as much as they will eat within a few minutes.
  • Submerge the food so that it sinks, preventing the fish from gulping air at the surface.


If this makes no difference then it is likely that the problem is caused by either an internal infection or growth, or by the arrangement of the internal organs (which is untreatable). Internal infections are very difficult to treat without prescription drugs, and so if the fish fails to respond after a few weeks of general medication then it is not likely to. In such cases the only options left are to consult your vet with regards to stronger medications. If the condition appears to be untreatable then a judgement must be made as to whether the fish is suffering. If it is not able to feed and appears to be in distress then the kindest thing to do may be to put it down. In most cases however, they continue to live normal lives save for the fact that swimming progressively becomes more difficult.

It is important to note that swimbladder problems are predominantly restricted to extreme forms of fancy goldfish, and that in many cases the condition is easily remedied. Provided the precautions mentioned above are taken and your fish are properly cared for, your fancy goldfish should remain happy and extremely healthy.