Understanding the Life Span of Goldfish

Goldfish (Cassius auratus) can make a great and wonderful pet. They’re surprisingly intelligent and very interactive. Goldfish are one of the most popular pet fish available, and it’s easy to see why. Of course, there’s more to caring for a goldfish than a simple bowl and some water. For their long-term health, there are a few key considerations when contemplating a goldfish for a pet.

Goldfish grow much larger than most people think. Although it varies between the standard (wild-type) and fancy goldfish, their ultimate adult size ranges from around 8 inches to nearly two-feet in length! A small bowl is not an appropriate home for a goldfish. An aquarium size of around 15-20 gallons PER goldfish is much more acceptable, due to various reasons.

While goldfish are very hardy fish and can live for a few years in a bowl, consider the impact this will have on the fish. They will quickly become stunted and unhealthy. Fancy goldfish have been inbred for so many generations (to bring out certain desirable physical traits), and their immune systems are often compromised in the process. This leaves them susceptible to many diseases, so good water quality is essential in their care, which is very difficult to maintain in a small aquarium or bowl.

Goldfish are also fast growers, and subsequently heavy feeders. They create a mess while eating. An ideal feeding regimen includes multiple small feedings per day (3-5) of a good quality fish food. Goldfish tend more to the herbivorous side of the diet spectrum, and their staple diet can be supplemented with common greens (romaine lettuce, seaweed, etc.).

Water quality in a goldfish aquarium should be monitored daily until a routine is established. With the amount of waste these fish can produce, the water parameters can fluctuate rather quickly, bringing down the quality of their water. Water changes and proper filtration will be necessary to keep your pet happy and healthy. A neutral pH (7.0) and zero readings for ammonia and nitrite are mandatory for good health. Nitrates (the end product of the breakdown of waste in the nitrogen cycle) should be kept at 50ppm or less. Testing the water to determine when a change should be done is necessary. Simple math can be applied. For example, a single goldfish in a 20g tank with a nitrate reading of 100ppm would require a minimum of a 50% water change, which would bring the nitrates to 50ppm. Ideally, smaller, more consistent changes are less stressful on the fish and allow for better health. Rather than diluting the nitrates in half, small changes over a few days will bring the levels down more slowly. Small, consistent changes should keep all your levels in check.

Success for keeping goldfish is often measured by “a few years” in a bowl. Consider that a goldfish has a natural lifespan of 25 years or more, coupled with the average size of a fancy goldfish at 8-10″, and maybe you can understand why keeping these beautiful and intelligent creatures in a 1g fishbowl is borderline animal cruelty.

If you’ve ever had the pleasure of keeping a goldfish long-term, you’ll no doubt recognize that these are far from the dumb animals people make them out to be. Goldfish (and indeed, most other fish as well) will recognize their owners and be much more interactive than people would ever think. My parents have a large pond with many goldfish and koi in it. One summer, I was hanging out by the pond feeding the fish with my hand in the water, when once of the fish swam into my hand to be cupped there. I gently scooped the fish out and threw him out into the pond a little. Amazingly…this little fish swam right back to me and into my hand, and we proceeded to do this a few more times. From what I could tell, this supposedly dumb little animal was thoroughly enjoying its short flights through the air. Given proper housing and care, I’m sure you’ll find out that a goldfish (even a twenty-five cent feeder at a pet store) will grow into a more amazing companion than you could ever suspect.

When considering a goldfish, please take into consideration the proper care of these beautiful animals. They are not expensive, but that doesn’t make them any less a living creature than a dog, a cat or a person. They’re relying on YOU for their proper care and maintenance. Treat them with the respect and love the deserve. You’ll find that after a while, your goldfish will be almost a friend, so please consider treating them like one.