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Variety of Goldfish

Bubble eye

Carassius auratus

One of 12 varieties of Carassius auratus · See all varieties →

Also known as Water-bubble eye goldfish, Toadhead goldfish

FreshwaterFish

Bubble eye (Carassius auratus)
Lawrencekhoo · CC BY-SA 4.0

Varieties · Carassius auratus

See all 12 →

Care at a glance

Temperature
64–73°F
18–23°C
pH
6.5–8.0
Adult size
5.9 in
15 cm
Minimum tank
20 gal
75 L
Temperament
Peaceful
Social behavior
Social
Tankmates
With caution
Swim level
Middle
Difficulty
Difficult
Breeding
Medium
Rarity
Common
Family
Cyprinidae
Origin
A delicate dorsal finless fancy goldfish bred in China from domesticated Carassius auratus, whose wild ancestor lives in slow East Asian freshwater.

Overview

The bubble eye is a slow, delicate fancy goldfish with a large, fluid-filled sac under each upturned eye. It belongs in a calm tank with other slow fancies, and it is a fish for experienced keepers.

Did you know

A bubble eye's sac can sometimes refill or regrow over several weeks in clean water after it deflates or tears. It rarely returns to its original size.

Caring for the bubble eye

Give a bubble eye at least 20 gal (75 L) and a calm tank free of hazards. Its sacs tear easily on sharp objects and filter intakes, and a torn sac often becomes infected. Leave out sharp decor entirely and use silk or soft live plants only.

A goldfish has no stomach, so food passes through quickly, and a well fed bubble eye makes a lot of ammonia. Run strong filtration, with a covered intake or a sponge filter to protect the sacs. Keep the water very clean and stable, at 64 to 73°F (18 to 23°C) and a pH of 6.5 to 8.0.

Feed a varied diet of slow-sinking pellets, vegetables and the odd frozen food. Give it extra time to find each meal.

Bubble eyes are peaceful and social, and each one wants the company of its own kind. Keep them only with other slow fancies with poor vision, such as celestials. Breeding them is moderately difficult.

Good to know

The bubble eye's sacs are pouches of skin, a fixed trait selected purely for appearance. They wobble as it swims and impair both its vision and its swimming. It also has no dorsal fin, so it swims slowly and clumsily. It is one of the more fragile strains of Carassius auratus, in the family Cyprinidae.

In the wild

The bubble eye was bred in China from the domesticated goldfish. Its wild ancestor lives in slow freshwater across East Asia.

From published sources

Tank mates

Each fish here is named as a tank mate for the bubble eye by at least two published care guides. Every partner here handles cool water. The tank needs about 20 gallons (75 liters) for the first fancy goldfish and 10 gallons (38 liters) for each extra one.

Sources: Practical Fishkeeping, Aquarium Co-Op, Fishkeeping World, Aquarium Source, Tropical Fish Hobbyist.

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Common questions

Is a bubble eye a different species from the goldfish?

No. A bubble eye is a variety of the goldfish, Carassius auratus. It is kept the same way apart from difficulty, adult size, tank size and temperature.

What size tank does a bubble eye need?

A bubble eye needs at least 20 gal (75 L). It spends most of its time in the middle.

What does a bubble eye eat?

A bubble eye eats a varied diet of slow-sinking pellets, vegetables and the odd frozen food. It needs extra time to find each meal.

How big does a bubble eye get?

An adult bubble eye reaches about 5.9 in (15 cm).

What fish can live with the bubble eye?

Published care guides name weather loach, bristlenose pleco, bulldog pleco and variable platy, among others. Every partner here handles cool water. The tank needs about 20 gallons (75 liters) for the first fancy goldfish and 10 gallons (38 liters) for each extra one.

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