Goldfish care guide
Goldfish (Carassius auratus) — minimum tank 150 L, temperature 18-24 °C, pH 6.5-8.
Overview
The Goldfish (Carassius auratus) is a cyprinid fish domesticated in China over a thousand years ago from wild Asian crucian carp stock. Hundreds of selectively bred varieties exist, ranging from the slender Common and Comet forms to the rounded, double-tailed Ranchu, Oranda and Telescope-eye fancy types.
Taxonomy
- Family: Cyprinidae
- Genus: Carassius
- Scientific name: Carassius auratus
Habitat
Wild ancestors inhabit slow, well-vegetated freshwater of East Asia. Feral populations have established on every continent except Antarctica and are considered invasive in many countries. Goldfish tolerate a wide temperature range from cold to subtropical waters.
Tank requirements
- Minimum tank volume: 150 L (39.6 US gal)
- Adult size: 15-30 cm
- Temperature: 18-24 °C (64-75 °F)
- pH: 6.5-8
- GH: 5-20 °dGH
- Water flow: moderate
- Lifespan: 10-25 years
Diet
An omnivore, feeding on plant matter, detritus, insect larvae and small invertebrates. In aquaria a sinking goldfish-specific pellet supplemented with blanched vegetables (peas, spinach, cucumber) and occasional gel food prevents the swim-bladder issues common to round fancy forms.
Compatibility
Peaceful and social. Single-tailed goldfish (Common, Comet, Shubunkin) are active, fast and grow large; they suit ponds or very long tanks. Fancy double-tailed forms are slower swimmers and should not be combined with single-tailed types or with fin-nipping species; tropical fish are unsuitable due to differing temperature requirements.
Breeding
An egg-scatterer. Spawning is triggered by a temperature rise after a cool winter period; eggs are deposited on plants or spawning mops and parents readily consume them. Fry are dark-coloured and acquire adult colour after several months.
Conservation status
IUCN Red List: Least Concern. The domesticated population is essentially limitless; wild Carassius auratus remains common across its native East Asian range.