Goldfish Care Sheet
IntermediateCarassius auratus · fish
Goldfish are a classic coldwater species that grow large and produce heavy waste. They require spacious, well-filtered tanks with cooler temperatures.
Quick care stats
Adult size6-12 inches (depending on type)
Lifespan10-15 years
Min tank size20-40 gallons
Water temp65-75 F
pH6.5-7.5
Hardness5-20 dGH
TemperamentPeaceful
Group / schoolingSolo or group of similar-sized goldfish
Tank matesOther goldfish; avoid fin nippers and small fish that fit in mouth.
DietHigh-quality sinking pellets or gel food, supplemented with blanched vegetables (peas, zucchini) and occasional bloodworms. Feed 2-3 times daily in small amounts.
What you need (full setup)
🔧 Aquarium tank (20-40+ gallons)Goldfish grow large and produce significant waste; need ample water volume.🔧 Canister filter (rated for 2-3x tank size)High biological filtration capacity to handle waste load.🔧 Adjustable heater (optional, set to 68-72 F)Maintains stable temperature; goldfish prefer cooler but stable conditions.🔧 ThermometerMonitor water temperature for stability.🔧 Substrate (sand or smooth gravel)Prevents injury; goldfish forage on substrate.🔧 Water conditioner (dechlorinator)Removes chlorine/chloramines from tap water.🔧 Test kit (liquid-based, for ammonia, nitrite, nitrate, pH)Essential to monitor water quality, especially nitrogen cycle.🔧 Live or silk plants (Anubias, Java fern) or smooth decorProvides hiding spots and enrichment; avoid sharp decor that can injure goldfish.
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Common health issues
- Swim bladder disease
- Ich (white spot)
- Fin rot
⚠️ For any sign of illness (not eating, lethargy, swelling, retained shed), see a qualified exotics vet. Care sheets are general guidance only.