Dealing With Buoyancy Problems



A fairly common problem with goldfish, especially the more fancy types with egg shaped bodies, is difficulty in maintaining their balance. As a result the fish tend to either float to the water surface or sink to the tank base when they are at rest. In some cases the fish may float upside down.

The cause of this imbalance is due to a problem with the goldfishes swimbladder. The swimbladder is a two chambered air-sack located in the body cavity that the fish uses to keep its balance in the water while it is at rest.


Swimbladder problems can be triggered by a number of things:

* Chills and sudden changes in temperature.

* Pressure on the swimbladder from food in the gut of the fish.

* Air in the fishes gut - either taken in with the food, or as a result of fermentation in the gut.

* Bacterial infection of the swimbladder (less common).

* Parasite infection of the swimbladder (less common).

The fancy bodied fish are generally more vulnerable to these problems because their swimbladder is closely compacted between the gut and the 'backbone' of the fish which itself may be distorted.


More often than not the problem is triggered by the eating habits of the goldfish. To find out if this is the cause the first step is:

1) Starve the fish of all food for 48hrs. Goldfish will come to no harm from this temporary fast. If the fish noticeably improves then you should alter the diet to reduce the risk of the problem occurring again (see below).

2) Double check the water quality. Are you carrying out regular partial water changes? Is the filter functioning properly? Is the temperature stable, or is it fluctuating due to a nearby draught/window/heater?

3) If there is no improvement, reduce stress to the fish by adding some tonic salt at the rate of one heaped teaspoon per gallon of water. This salt will remain in the water until it is diluted by partial water changes.

4) If you suspect an underlying disease problem, it may be worth trying Interpet No. 13 "swimbladder treatment".


Changing the diet can greatly reduce the incidence of swimbladder problems. Finding the best food for your goldfish can involve some trial and error, as different fish respond differently to changes in diet. This is partly due to the way that your goldfish eats. Some individuals eat floating foods very rapidly and can take in a lot of air at the water surface, other fish may have problems digesting certain types of food. From our experience the following can help.

* Do not overfeed! Most modern fish foods are very concentrated, a small amount is sufficient. Goldfish are very greedy and will easily eat more than they should.

* Avoid dried flake food. Holding the flakes below the water surface can help, but it is probably better to avoid these foods altogether if you are getting swimbladder problems.

* Try alternative floating foods - e.g. 'Hikari 'Baby Pellet'. 'Tetra' Gold Medal goldfish pellets; 'Tetra' Floating goldfish sticks.

* Try slow sinking granular foods - e.g. 'Tetra' Prima

* Try fully moistened foods such as 'Gamma' frozen bloodworm.

* Try sinking/below water foods such as 'Tetra' "Fish Treat" tablets, or better still Hikari "lionhead" food.


If your fish - despite a temporary fast, checking the water conditions and changing the diet - shows no signs of improvement after 3 to 4 weeks, it may unfortunately have permanent damage to its swimbladder. In these cases it is virtually impossible to cure. However, goldfish can often live to a good age despite these problems.