
AI-generated image
Carassius auratus
The black-coloured line of the Chinese bubble eye, a goldfish carrying a large fluid-filled sac under each eye. It has no dorsal fin, upward-facing eyes, and is a poor swimmer.
The black bubble eye is the black-coloured line of the Chinese bubble eye goldfish. The breed descends from a fish whose conjunctiva below the eye became enlarged; it was refined among the Chinese upper classes, spread to ordinary keepers in the early 1900s, and first reached Japan in 1958. It has a ranchu-type body with no dorsal fin, eyes that point upward, and a balloon-like sac on each side of the head. The sacs contain lymph; a ruptured sac is rarely fatal but almost never regrows symmetrically. Because the fish swims poorly, strong filter intakes and net handling both need care. The black colour may fade with age into red or variegated patterning, and how well it holds varies greatly between individuals.
Source: Wikipedia (CC BY-SA 4.0)
The Black Bubble Eye lives 5-10 years.
The Black Bubble Eye grows to 10-15cm.
The ideal temperature for the Black Bubble Eye is 15〜28℃.
Origin
China (developed variety)
Lifespan
5-10 years
Size
10-15cm
Sources: FishBase (Carassius auratus) / Keihan Nishikigoi Center: goldfish water management / Kingyo Hitosuji: Bubble Eye
Edited & verified by: BreederDirect editorial team
The taxonomic, regulatory, and husbandry data on this page are compiled and verified against the authoritative primary sources below.
Sources: CITES Appendices (species not listed) / FishBase (Carassius auratus)
Regulations may change. Always verify the latest information with the relevant authorities.
Find listings for this species
Temperature
15〜28℃
Prepared foods, frozen bloodworms
Bright lighting is unnecessary. The breed is viewed from above, so light need only be strong enough to show the shape of the sacs. Avoid very bright surroundings to help hold the black colour.
With no dorsal fin and poor swimming ability, keep the flow gentle. Use a simple layout so the sacs cannot catch on filter intakes or sharp ornaments.
Do not mix with fast wakin-type fish or comets: this fish loses out at feeding time and its sacs may be pecked. Pair it with equally slow breeds such as the celestial eye.
The sacs tear easily during water changes and netting. Move the fish out before changing water, and support it with a hand over the net. A torn sac does not recover.
Advanced. This is an advanced-level species. It requires specialized equipment and advanced husbandry skills with precise environmental control.
The ideal temperature for Black Bubble Eye is 15〜28℃. Avoid sudden temperature changes and maintain a stable environment.
The average lifespan of Black Bubble Eye is 5-10 years. With proper care and nutrition, they can live a long and healthy life.
Black Bubble Eye typically reaches 10-15cm as an adult. Size may vary depending on care conditions and individual genetics.
Black Bubble Eye feeds on: Prepared foods, frozen bloodworms. Aim for a balanced diet with appropriate feeding frequency.
The price of Black Bubble Eye varies significantly depending on variety, size, and individual quality. Check our market price page for the latest pricing information.
Last updated: September 17, 2026