Bubble Eye goldfish

The Bubble Eye is a variety of goldfish, characterized by the fluid-filled sacs it has underneath both eyes. It is a “fancy” variety, its unusual shape the result of many years of selective breeding.

The Bubble Eye lacks a dorsal fin, and has a double tail. It occurs in a number of colors, including gold, red, black, white, red-and-white, and calico. Its eyesacs typically start small, and then grow as the fish does, partially occluding its vision. Bubble Eyes can reach to 6 to 8 inches (15 cm) in length.


While Bubble Eyes are as inexpensive and easy to find as other fancy varieties, they are not recommended for beginning fishkeepers because their delicate eyesacs can be easily damaged by rough or sharp surfaces, or by filter intakes. A Bubble Eye should never be kept in a tank with anything abrasive, such as most rocks. Should the eyesac become punctured, it is important that the owner keep the water especially clean, or use a topical product like Melafix, so as to stop the puncture from becoming infected. A punctured sac will eventually heal and grow back, although it is almost always scarred or misshapen after healing.

Additionally, because their eyesacs can grow quite large and hamper their swimming somewhat, it is important that Bubble Eyes only be kept with other slow goldfish (other Bubble Eyes, telescopes, and Celestial Eyes are optimal, but many of the fancy varieties are fine as long as the individuals are not aggressive, and as long as the bubble eyes get enough food).

Bubble Eyes prefer tanks with little or no current. They should be kept in a minimum of 10 gallons (38 liters) of water per fish, although 20 to 50 gallons (75 to 200 liters) may be optimal, depending on the size of the fish. Although goldfish are cold water fish, fancy varieties prefer that water temperature be kept between 76 and 78 °F. At these temperatures, however, it is crucial that the surface of the water be agitated enough to provide adequate oxygen (lethargy and gasping are common symptoms of oxygen deprivation, which may occur in still water anywhere above 70 °F). Using sufficient air stones and bubble walls to achieve reasonable oxygen exchange, Bubble Eyes and other fancy goldfish varieties may remain healthy up to 90 °F.

As with most aquarium fish, water changes should be performed every week in a sufficient amount to keep nitrate levels below 40 ppm. If large amounts of water need to be changed to achieve this, it is likely that the tank is too small.

Being a large-bellied ‘fancy’ variety, Bubble Eyes can get intestinal problems if they eat too much processed food (as it tends to expand in the stomach), and should generally be fed sinking pellets as well as a variety of fresh fruits and vegetables to avoid excessive ingestion of air. Excessive feeding of processed fish foods, especially floating-type foods, can cause constipation and swim bladder disease. Symptoms are an inability to remain upright, floating at the top of the tank, or sinking to the bottom. (These symptoms can also be caused by poor water quality or by bacterial infection.) Fish with swim bladder problems should be fasted for 24 hours and then fed frozen green peas. Additionally, if using floating-type packaged fish food, it is advisable to soak it in water to allow it to expand before it reaches the fish’s stomach.