Goldfish (Common)

Carassius auratus was domesticated in ancient China over a thousand years ago and exists in hundreds of cultivated forms today. The common single-tailed variety is the hardiest and most adaptable, tolerating temperatures from near-freezing to warm subtropical conditions. It can also tolerate mild brackish salinity, making it a crossover option for low-salt systems.

Water: 10–24 °C, pH 7.0–8.0, specific gravity 1.000–1.004; cold to temperate freshwater preferred. Tank: 120 L minimum; strong filtration essential due to high waste production; cold-water setup. Feeding: Omnivorous; quality goldfish pellets, blanched vegetables, and occasional frozen foods. Behaviour: Social and peaceful; keep in groups; active foragers that dig and uproot plants. Compatibility: Cold-water community fish; unsuitable for tropical tanks; pairs well with Koi in ponds.