Goldfish affected by supersaturated gases might show symptoms such as uncontrolled swimming; gasping at surface; bulging eye, known as pop eye, bubbles escaping from mouth or gills; raised areas that look like tumors, which are actually air pockets or bubbles under the skin
Tap water often comes out of the faucet saturated with gases, which are
actually concentrated levels of oxygen that goldfish cannot tolerate. They can
literally suffocate from these extreme amounts of oxygen. You might have noticed
the minuscule bubbles in a freshly filled water glass. As an experiment, fill
one glass with tap water from a faucet turned on full blast. Fill another glass
with tap water with the faucet turned on at a slow stream; and you'll see the
difference. Now, take the glass filled with the bubbles and using a whisk; stir
it briskly for several moments. You'll see that the bubbles
Check the glass walls of your aquarium for these tiny bubbles; when visual, supersaturated gases are present and may be injuring your fish.
If your faucet has extreme amounts of gases, try removing the cap from the end of the faucet; these caps which contain a screen increase pressure which increase the amount of supersaturated gases in the tap water.
The goldfish in the photo below has an air pocket at the base of the dorsal
fin; looking much like a tumor.
To eliminate supersaturated gases in tap water; work fresh water over by pouring it a few times. Hold the container high over the fresh water tub; let it hit hard; this breaks up the gases.
Increase the surface action in your tank, aquarium or pond by adding a pond pump. The action of the pump; pulls the water along with the gases into the intake valve shooting a powerful jet of water to the top of the tank where the gas is released; making the water safe for goldfish.
Open the top of your aquarium so the surface of the water is exposed to fresh air.
If after increasing your surface action and eliminating the supersaturated gases in your tank water; your goldfish shows signs of distress; it may benefit from a salt bath. Salt Bath