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Goldfish

Carassius auratus · family Cyprinidae

Also: Common Goldfish

Goldfish (Carassius auratus) — aquarium fish
Franky44 / Wikimedia Commons / CC BY-SA 3.0

Parameters

Temperature
18–22 °C
pH
6.5–8
Hardness
5–19 °dGH
Tank volume
from 150 L
Maximum size
up to 30 cm
Group size
min 2, ideal 3
Temperament
Peaceful
Swimming zone
Throughout
Difficulty
Intermediate
Lifespan
10–20 years
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Description

The goldfish is a cold-water crucian carp, domesticated in China more than a thousand years ago. Many fancy strains exist: veiltails, telescopes, orandas, ryukins, and more.

The classic mistake is keeping them in round bowls under 30 L. The result is spinal deformity, kidney failure, and a lifespan of 1–2 years instead of 10–20.

Care

Volume

Minimum 150 L for a pair of fantails. For long-bodied forms — a pond or 400+ L.

Filtration

Goldfish are big and messy. A filter rated at 6–10× volume per hour, plus weekly 30% water changes.

Feeding

Sinking pellets for cold-water fish (floating pellets cause air-swallowing and swim-bladder problems in fancy forms) + blanched peas and zucchini.

Compatibility

  • Guppy

    Poecilia reticulata

    Different temperatures, and goldfish eat guppies.

    Danger
  • Neon Tetra

    Paracheirodon innesi

    Incompatible temperatures; neons become food.

    Danger
  • Common Pleco

    Hypostomus plecostomus

    The pleco may latch onto the coldwater fish.

    Danger
  • Zebra Danio

    Danio rerio

    Limited temperature overlap; the danios may go hungry.

    Caution

FAQ

Сколько живёт золотая рыбка?
В аквариуме хорошего объёма — 10–20 лет; в круглых вазочках — менее 2 лет.
Goldie editorial team — collective profile photo
AuthorGoldie Editorial

Goldie editorial team

Practising aquarists with a combined 30+ years of experience · Biologists and editors, fact-checking against FishBase and Seriously Fish · Every piece is reviewed by a qualified ichthyologist before publication

Goldie Science Board — collective scientific review panel
Reviewed byGoldie Science Board

Scientific board — ichthyologists and veterinarians

Ichthyologists and veterinarians with university degrees · Reference FishBase, Seriously Fish and peer-reviewed literature · Sign every reviewed article with their credentials shown

Sources

  1. FishBase: Carassius auratus · FishBase · 2026-05-22
  2. Seriously Fish: Carassius auratus · Seriously Fish · 2026-05-22