Goldfish Care Guide — The Most Misunderstood Fish

Goldfish are sold as beginner fish and kept in tiny bowls — but this setup kills them within months. Goldfish are actually one of the messiest, most demanding freshwater fish. Done right, they live 10-15 years. Here's how to do it right.

Goldfish need big tanks

A single fancy goldfish needs a minimum of 20 gallons. Each additional goldfish needs 10 more gallons. Slim-bodied goldfish (comets, shubunkins) do best in outdoor ponds. Fancy goldfish (orandas, ryukins, telescope eyes) are better suited for aquariums. Never put goldfish in a bowl — they'll live a few months instead of a decade.

Filtration: overfilter always

Goldfish are poop machines. They produce 3-5x more waste than tropical fish of the same size. Your filter needs to be rated for 2-3x your tank size. A canister filter (Fluval 307 or similar) is ideal. Hang-on-back works but needs more frequent cleaning. Do 30-50% water changes weekly — goldfish are that messy.

Temperature: goldfish are cold water fish

Goldfish prefer 65-72°F — cooler than tropical fish. No heater needed in most homes. They can tolerate temperatures from 50-75°F. Do not keep goldfish with tropical fish — the temperature requirements are incompatible. Koi and goldfish make great pond companions.

Goldfish food

Feed goldfish-specific food — not tropical fish flakes. Goldfish food has less protein and more plant matter, matching their omnivorous diet. Soak pellets for 30 seconds before feeding to prevent them gulping air (causes buoyancy problems). Feed small amounts twice daily.