How Long Do Goldfish Live?

Goldfish swimming in an aquarium

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When you first bring home your goldfish, how long can you expect them to live? Is a 6-or-7-year-old goldfish dying from old age? Absolutely not. For most comet goldfish, you can expect at least 20 years, with the world record goldfish living for 42 years! Most of the time, as they get larger, goldfish start to get too large for a small aquarium, resulting in poor water quality and stress. This frequently results in secondary illness due to decreased immune function from chronic stress. In order to take proper care of your goldfish in their later years, be prepared for 30 gallons or more per fish. With proper care, goldfish can easily live a long and healthy life.

Fancy vs. Standard Goldfish

There are a wide variety of goldfish in the pet industry. With round bodies, protruding eyeballs and ornate fins, fancy varieties of goldfish can be quite elaborate. In order to obtain these unique individuals, many generations of goldfish have been cross bred. This has led to fancy goldfish having shorter life spans than standard comet goldfish. Most fancy varieties of goldfish should live into their teens, but 20 years is not common.

What Can You Do to Help Lengthen Lifespan?

In order to help your goldfish live a long and happy life, proper care of goldfish comes down to providing them the correct environment and diet. These will both change as your goldfish gets older and grows larger.

Correct Environment

All fish may start small, but many goldfish have the potential to grow as large as a dinner plate! Contrary to popular belief, goldfish do not “grow to the size of their container.” Starting your goldfish in a 20-gallon tank (that’s per fish!) will work for the first few years, but plan on upgrading them as they grow over the years.

Goldfish are hungry fish and do not convert their food into mass very well, so they produce a lot of waste. This waste ends up in their aquarium water, causing water quality issues that requiring frequent cleaning. When fish are swimming in gross water, their immune system does not work well and the fish will get sick from secondary infections from environmental bacteria and any lingering
parasites. This is the most common cause of goldfish death that is commonly attributed to “old age,” when it actually has to do with your fish’s limited space and poor water quality.

Diet and Feeding

There are a wide variety of goldfish diets on the pet store shelves. Often, owners are overwhelmed with options and settle on flashy packaging or pricing to guide their decisions, neither of which has any influence on food quality. When it comes to goldfish diets, owner’s should pay attention to the protein and fat content of the diet that is listed on the label. Goldfish require approximately 30% protein for proper body maintenance. Growing juveniles will require more protein, around 35-45%. Fat requirements for goldfish are low due to their limited activity. For maintenance, your goldfish will require around 6% fat, with young fish and reproductively-active fish requiring around 10% fat in the diet.

Flake diets are only for tiny fish. Once your goldfish can eat a pellet, they should be switched over from flakes to pellets. Goldfish pellets come in very small sizes these days, so size is not an excuse to keep feeding your fish flakes. Pellets retain their nutrition significantly better than flakes due to their lower surface-to-mass ratio. Your fish may not like the switch because flakes smell and taste better than pellets. Use some tough love and tell your fish it’s better for their overall health, not to mention less waste for you to clean! Remember to replace your container of fish food every six months to maintain good vitamin content.

Geriatric Goldfish Care

Once your goldfish actually reaches “geriatric” age in their late teens and early 20s—or early teens for fancy varieties—you can expect to see some changes in their behavior. As they get older, expect your goldfish to not swim as much and take extended rest periods on the bottom of their aquarium. You will need to keep their water quality and tank clean in order to support them in their later years. Some goldfish may start to eat a little less, but this is not common. Older goldfish may be more selective about their diet, so offering a variety of pellets may be required in order to maintain their nutrition. Do not just feed them treats, such as dried or frozen shrimp. All fish require a well-rounded diet that most pellets can provide, made from a mix of proteins and veggies.

Overall, goldfish are one of the most long-lived pet species, so a death at less than 10 years old is usually not age-related. More often, as they grow, goldfish max out their space and resources. What is appropriate for a small goldfish will not be the same for life. Adjust the aquarium size and filtration as your pet goldfish grows to provide a proper habitat for a long and happy life.