Floating goldfish: Causes and cures

by Owen James

Goldfish suffer more than their fair share of gruesome ailments, of which floating listlessly at the surface is a common one.

Floating doesn’t seem to happen much with tropical fish, yet you can barely walk past a typical pet shop’s bank of coldwater tanks without seeing at least one goldfish bobbing about at the surface, or even lolling upside down.

The good news is the floating often corrects itself after a few days, and it’s rarely contagious. The bad news is affecting a cure to permanent buoyancy problems can be impossible.

What causes goldfish to float?

Invariably the cause is a swimbladder problem in the affected goldfish. This often manifests itself in floating behaviour, although it can also be seen in fish that sink to the bottom of the tank. In both cases the fish is unable to use its swim ladder to maintain the proper position in the water.

There are many causes of swimbladder problems, and most are difficult to consistently treat, in part because it’s difficult to tell exactly what’s wrong with your fish.

Common causes of swimbladder problems include:

  • Intake of excessive air when eating from the surface
  • Build-up of gas within the swim bladder
  • Bacterial infection leading to an accumulation of fluid in the swimbladder
  • Physical damage
  • Incorrect internal growth, or even a tumour

Treating floating goldfish

If the fish doesn’t right itself after a few days then there are a few different treatments you can try. Unfortunately none of them is guaranteed to work.

Starvation or an exclusive vegetable diet

Stop feeding the fish and see if it’s able to expel the gas over a few quiet days. Alternatively, try feeding only crushed fresh peas. Sometimes this helps the fish to purge its insides of excess gas.

Increasing the water temperature

Raising the tank temperate by a few degrees (to a maximum of about 24 degrees Centigrade) can help a fish rid itself of excess gas. Like the starvation cure, it won’t work if there’s a more serious physical problem with the swimbladder.

Try adding some salt to the water

An old-timers cure is to add salt to the water. Sodium chloride, sold as tonic salts in fish shops, can occasionally work a miracle cure with goldfish (be careful with other species of fish in the tank that may not be able to tolerate salt in the water). Add a couple of grams per litre to the tank, or else treat the affected fish with a prolonged bath. Always follow the instructions on the tonic salt packaging.

You could try an anti-bacterial remedy

Several anti-bacterial medications are available. In my experience they seldom do much with serious buoyancy problems, but provided the instructions are followed carefully, it won’t hurt more than your wallet to try.

If your fish doesn’t respond to treatment, you may need to consider putting it to sleep, particularly if it’s suffering distress.

Buoyancy problems seldom affect more than one goldfish at a time, so if the problem recurs look for underlying problems with your aquarium. You might try to ensure dried foods are sinking quickly to avoid excessive air intake at the surface.

Making sure the tank is adequately filtered and doing regular water changes will go a long way to preventing any problems in your fish tank.

Check out Katy's Tropical Fish Guide for more aquarium info.

This guest post is by Owen James

Besides editing AquaDaily, Owen also writes for the Goldfish Care Guide, a website dedicated to keeping our orange-finned friends in fine fettle.

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{ 3 comments… read them below or add one }

Susan 01.20.09 at 11:29 pm

Good ideas. I fixed my goldfish’s problem with an anti-bacterial remedy, I forget the name sorry!

Rachell 10.28.11 at 1:29 am

This article help me a lot with my goldfish. I cleaned my tank first, then dissolved some sodium chloride (got it from my water softener) into a glass of hot water and added it to my tank in small doses. I’m also not going to feed him until tomorrow sometime. He is doing better already!

Christina @ Complete Goldfish Care 04.07.12 at 12:00 am

Goldfish are actually very hardy if kept in a healthy aquarium environment. Of course, if they’re just thrown into small glass bowls without adequate filtration or space, you’re bound to run into problems.

And I admit – buoyancy problems are common with goldfish, especially the fancy varieties. Fancy goldfish are more sensitive to poor water quality than common varieties and will likely be the first ones to gasp for oxygen at the water surface if the aquarium isn’t properly maintained.

Good read!


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