The Joy of Goldfish | The Pet Works

The Joy of Goldfish

When I talk with people about my fascination for fish and how many tanks we have throughout our home (20 freshwater tanks) one of the most common questions I’m asked is if they are all goldfish. Most likely this is because the goldfish (Carassius auratas) is one the most commonly kept aquarium fish. They are also one of the earliest fish to be domesticated over 1,000 years ago in China. They were introduced in North America around 1850 and quickly gained in popularity throughout the U.S.

Through the years, selective breeding has produced over 100 types of goldfish. They have many coloration patterns, fin and body shapes. They can be solid white, yellow, orange, brown and black or have combinations of these colors. Goldfish are an easy fish to keep as long as provided the proper habitat and healthy water conditions are maintained.

Most likely when hearing the word goldfish and the visual of a goldfish in a bowl comes to mind because of depictions of these fish in books or other forms of media. Unfortunately this has led to the belief they are able to be kept in a bowl without filtration and aeration. Goldfish cannot and should not be kept in a bowl. This type of habitat is also most likely the cause for the myth that goldfish have short lifespans. Goldfish are actually a hardy fish with a life span of 10-20 years (cases of 30-40 years have been documented) as long as they are provided the proper habitat and care.When considering owning a goldfish keep in mind a healthy goldfish will not be a “shortterm” pet. The most common cause of a short life span in a goldfish is poor water conditions and over feeding.

Goldfish habitat requirements are at least a 10 gallon tank for a smaller species if only keeping one or two fish. If more than two or for the larger varieties available a tank size of 20 gallons or more is needed. They will also require a filtration system, an air pump for additional oxygen and water movement is also important. A light source is also important because goldfish will gradually turn to a grayish coloring over time if not provided with light. The color change is not harmful to them but most likely if you purchase a vibrant fish you will want to keep them a vibrant color instead of gray. You can choose to have gravel substrate if desired or you can choose to not have gravel or other substrate. Goldfish will eat or uproot most live plants placed in a tank but there are a few plants such as Anubias or Cryptocoryne that can survive with goldfish as long they are not uprooted. Plastic or silk plants are more durable and easy to care for. Goldfish are “cold-water” fish and do not need a heater. They are best kept in a water temperature of 65-72 degrees. As always when setting up a new aquarium the water will need to be treated with a water conditioner and the tank water will need to be “cycled” to ensure it has the beneficial bacteria and it does not have high ammonia or nitrite levels. If you have questions about the proper way to cycle the tank water you can email me or refer to my previous article about the cycle process. Water changes and tank cleanings are important for all fish but especially for the goldfish species. They do not have stomachs which mean they will quickly produce waste from what they eat. They also do not have the ability to know when to stop eating as they never will feel “full”. Since they will produce waste quickly the waste will quickly turn into ammonia and disrupt the water conditions. This is not a problem in the wild because of constant water flow.

Goldfish are omnivore which means they can and will eat both plant and animal material. They enjoy scavenging for food and will eat anything they find on the substrate. They will eat the goldfish pellet and flake food you can purchase at a pet store which contain both the plant and animal matter. Goldfish specific food has less protein and more carbohydrates than the non-specific goldfish food. It is also a good idea to supplement their diet with shelled peas (without the skin) to reduce the risk of intestinal blocking. They also will benefit from leafy vegetables, bloodworms and brine shrimp. The bloodworms and brine shrimp can be found in most pet stores in a frozen form. Goldfish are not an aggressive fish and are friendly with other species of goldfish but they are not compatible with most other freshwater fish species because of the amount of waste they produce and because they are a cold-water species. Most freshwater fish need a heated tank and will not tolerate the waste produced.

The hardiest species to start out with if new to the hobby or owning a goldfish are the Common goldfish, Comet, fan-tails, Shubunkin, Black Moor and the Ryukin goldfish. If you have experience or are feeling more confident with owning goldfish you can look into the more fancy delicate types such as the Bubble-Eye, Celestial, Oranda or Lionhead species. Goldfish are a fun fish to own because they are known for being intelligent and receptive to their owners. They will greet their owners by holding eye contact with you or by coming up to the front of the tank and swimming around excitedly when approached. They are able to distinguish who their owners are over a short amount of time but if an unknown person approaches the tank they will actually hide. They also have great eye sight and they are able to see blue, green, red and ultra-violet. In fact after owning them for a couple months and if you feed them around the same time each day they will be able to anticipate feeding time by noticing the lighting changes throughout the day.

Another common myth about goldfish is that they have a short memory span. They actually have a memory span of up to three months and can be taught to eat food from their owner’s hands or even perform “tricks” by reacting to light signal combinations and positive reinforcement with food.

Even though they are interactive with their owners it is very important to know they must never be “pet” by a person. All fish have a protective layer over their scales called a slime-coat. This slime coat helps them from bacteria or water-born parasites.

If you are interested in looking at the variety of goldfish or getting an aquarium set-up we would love to have you come by one of our great Pet Works locations in Olympia, Astoria or Longview! Also if you have any question you can email me at  

By:  Tammy Dore