Goldfish Care Sheet
Carassius auratus
The classic pet fish — and much more demanding than most people realize. Goldfish are coldwater fish that need large tanks, heavy filtration, and should never be kept in bowls.
60–74°F
6.5–7.5
20 gallons
10–15 years (up to 25+ with proper care)
6–12 inches (15–30 cm) for common; 4–8 inches for fancy varieties
2+ (social fish; 20 gallons for first fish, 10 per additional)
Easy. Egg scatterers triggered by temperature changes (simulating spring). Very prolific — can produce hundreds of eggs.
Diet & Feeding
Omnivore — goldfish-specific pellets/flakes, blanched peas (helps digestion), frozen foods, vegetables. Avoid generic tropical fish food.
Natural Habitat
Domesticated from Prussian carp in China. Coldwater fish that prefer temperatures below 74°F. Need high oxygen levels.
Care Tips
NEVER keep in a bowl — minimum 20 gallons for one goldfish
Coldwater fish (60-74°F) — do NOT keep with tropical fish
Produce enormous amounts of waste — need heavy filtration (2x rated capacity)
Can live 15-25 years with proper care — they're a commitment
Fancy goldfish (orandas, ryukins) need slower water flow than commons/comets