Beginner's Guide to Caring for Goldfish

Good goldfish husbandry will help your fish live a long, healthy life.
i Goldfish image by Lucy Cherniak from

Goldfish are frequently marketed as beginner's fish, leading many people to believe they require little to no care. Goldfish require specific water conditions and husbandry, but a proper setup can greatly minimize the long-term care goldfish require and will greatly reduce their risk of disease.


Goldfish can thrive in either an aquarium or a pond, but they must have ample space. These fish can grow to 10 inches or larger, and continue growing for their entire lives. At minimum, fish must have room to swim and this generally means at least 10 gallons of water per fish. Much larger quantities of water will improve fish health.

Water Basics

Goldfish are cold-water fish who thrive at temperatures between 62 and 70 degrees Fahrenheit. Temperatures outside of this range can result in lethargy, anorexia and other health problems. Fish kept outside will hibernate when the temperature drops, but must have an air stone to keep ample oxygen in the pond during the winter. Indoor fish need consistent temperatures. Goldfish can be messy eaters, so it's important to drain 10 percent of the tank water and replace it each week. Add a water dechlorinator to the new water before putting it in the tank. Maintain water pH at or near 7.4.


Although goldfish don't typically need a heat light, they do need regular light cycles. Goldfish who live in dark containers may lose their color and have difficulty regulating their sleep/wake cycles. Give your goldfish 12 hours of direct light by installing an aquarium hood with a built-in bulb. Outdoor fish don't need artificial light. A light timer will help you ensure that the light cycles are regular and can turn the light off for you at night.


Goldfish are omnivores, which means they eat both plants and animals, and scavengers, which means they will eat just about anything. While they can subsist on fish flakes, they are much healthier when they eat a varied diet. Give your goldfish bloodworms, brine shrimp and mosquito larvae to ensure he gets sufficient protein. Collards, mustard greens, spinach and other dark, leafy greens are excellent vegetables for goldfish. Feed small quantities of fruit such as chopped raspberries or grapes a few times each week. Too much fruit can cause digestive problems.

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