A Beginner's Guide to Goldfish Care

The goldfish is one of the most commonly kept freshwater fish species across the entire globe. In this video we will provide all the information required to provide for their proper care and ensure their wellbeing and longevity. Follow along as we run through the must-know information regarding tank and water requirements, preferred habitat, feeding as well as a history of the species and common mistakes to avoid- all while setting up a temporary tank in the studio for our two new rescued Black Moor Goldfish!

Goldfish Quick Facts:

• Difficulty: Beginner-friendly

• Lifespan: Up to 30+ years

• Size: 1–18 inches (depending on variety)

• Diet: Omnivore

• Minimum Tank Size: 20 gallons for juveniles

• Water Temp: 65–75°F (18–24°C)

• pH: 6.5–7.5

Goldfish Care FAQ

Q: Why should I keep more than one goldfish?
A: Goldfish are social animals. When kept in groups, they interact regularly with each other. Having at least two provides companionship and encourages activity, which improves their overall well-being.

Q: How big of a tank do goldfish need?
A: Goldfish do not grow only to the size of their tank. A good rule of thumb is at least 5 gallons of water per inch of body length. A single juvenile goldfish should start in a 20-gallon tank or larger.

Q: Do goldfish need a heater?
A: Usually no. Goldfish are cold-water fish and thrive in temperatures of 65–75°F (18–24°C). Most homes provide a suitable environment without a heater, unless your room gets unusually cold.

Q: What are the ideal water conditions for goldfish?
A:

• Temperature: 65–75°F (18–24°C)

• pH: 6.5–7.5

• Ammonia: <0.1 ppm

• Nitrite: <0.2 ppm

• Nitrate: <50 ppm

Weekly 10–25% water changes and strong filtration are essential, since goldfish produce a lot of waste.

Q: What kind of filter should I use for goldfish?
A: Goldfish need efficient filtration to keep the water clean. Hang-on-back filters and sponge filters are popular choices. Look for filters that create good surface agitation to improve oxygenation.

Q: What decorations are safe for goldfish tanks?
A:

• Keep lots of open swimming space.

• Avoid sharp decor or small holes that could trap fish.

• Use large, smooth gravel or go bare-bottom for easier cleaning.

• Add hardy plants like Anubias or Java fern (though goldfish may nibble on them).

Q: What should I feed my goldfish?
A: Goldfish are omnivores and need variety in their diet. Offer:

• Goldfish-specific flakes or pellets

• Frozen and freeze-dried foods

• Vegetables like blanched peas or spinach

Feed small amounts 1–2 times daily—only what they can finish in a few minutes. Avoid overfeeding, as goldfish will eat continuously if given the chance.

Q: Can goldfish live with other fish?
A: Yes! Goldfish can live with other cold-water community fish such as white cloud minnows, zebra danios, and of course, other goldfish.

Q: How long do goldfish live?
A: With proper care, goldfish live 10–15 years on average, but some have been known to live 30+ years.

Q: What are common goldfish health problems?
A:

• Ich (White Spot Disease): White specks, rubbing, rapid breathing.

• Bacterial Infections: Cloudy eyes, sores, redness.

• Fungal Infections: Cottony white growths.

• Fin Rot: Frayed fins, redness at the base.

Keep water clean, quarantine sick fish, and use proper treatments such as aquarium salt, ich remedies, or antibacterial/antifungal products.

Q: What’s the difference between a goldfish and a koi?
A: Both are members of the carp family. Koi have a longer, slender body, a box-shaped head, and whiskers (barbels) near the mouth. Goldfish are shorter, rounder, and do not have barbels.