Bubble-eye goldfish

Carassius auratus

Paired sacs beneath the eyes and normally no dorsal fin

In the dorsal-finless bubble-eye form, distinctive sacs lie beneath and beside the eyes; they are not enlarged transparent eyeballs. Sac size and tail form vary, and a side image cannot judge bilateral symmetry.

Adult length: About 10 cm
Lifespan: Up to 30 years
pH: 7–8.4
Hardness: 5–19 dGH

Natural habitat: Wild habitats include rivers, lakes, ponds and ditches, often in vegetated still or slow water; ornamental goldfish are domesticated forms.

The sacs are vulnerable to injury. Avoid sharp decor and boisterous, highly competitive companions. Reported regrowth does not mean an injury is harmless. Swimming and feeding ability vary among forms. A shared species name or overlapping temperatures does not establish compatibility. Provide filtration, oxygenation and maintenance.

View comparison →

Appearance and identification

Large under-eye sacs distinguish bubble eyes from celestials; upward eye direction alone does not merge the forms.

Same-species behaviour

Assess individual swimming and feeding; a group size suitable for every form remains unknown.

Space requirements

A dimensioned adult housing plan remains unverified. Avoid small, unfiltered containers.

Diet and feeding

Use an appropriate goldfish diet with suitable varied foods, adjusting to condition and water quality.

Compatibility limits

Active single-tailed fish may outcompete slower double-tailed forms. Avoid fin nippers and overly competitive companions.

Aquarium environment

Goldfish may eat or uproot plants; aquarium illustrations do not establish plant safety.

Sources