Goldfish
(Carrasius auratus)
By Lindsay Mayer, Veterinary Assistant
NATURAL HISTORY
The goldfish is one of the most widely kept freshwater fish the world over. A domesticated descendant of the Koi, the goldfish has a long and storied past, originating in east Asia. This now massively popular fish originally farmed as food, its ancient ancestor was actually a silvery-gray color. This ancestor was known as “chi”. Occasionally, a vibrantly patterned or colored fish would be produced as a result of random genetic mutation. In the wild, these mutated goldfish would be eaten by predators. However, 9th century Chinese people began keeping these special “chi” fish in ponds, where they could be protected from predation (and becoming someone’s dinner!).
For a long time, these “goldfish” were unrecognizable from the silvery-gray wild fishes, and were wary of humans -- for about 100 years! So, how did the goldfish we know today come to be?
“In the Buddhist tradition, it is a good deed to set an animal free, especially if the animal is rare. So it became common practice throughout China for the rare coloured chi to be spared the stewpot and released into ponds. Official records document an accumulation of colourful chi in ponds around 975 CE.” (Goldman, 2014)
Eventually, both public ponds and those owned by the very wealthy began to explode with beautifully colored goldfishes. By 1240 CE, the goldfish had now become completely domesticated and separate from their chi ancestors, readily accepting of human interaction. At this point, there was no turning back -- people loved these brightly colored, interactive fish, and at once began selectively breeding to produce more and more varied breeds and colors.
These days, there are over 200 recognized breeds of goldfish available, but the vast majority available to the average pet owner fall under two categories: “common” or “single-tailed”, and “fancy” or “double-tailed” goldfish, with even more variations in body shapes and colors within each group. They can grow up to 12” in length (no, keeping them in a small tank will NOT stop them from growing!), and live between 5 and 30 years (the oldest ever recorded was 43!) depending on the breed. They are easily attainable, easy to keep, and long-lived. They have even been known to recognize and interact with their owners, making them an interesting aquatic housemate!
TANK SETUP & WATER QUALITY
With any aquarium setup, there are certain parameters that must be met, regardless of species. Perhaps the most important aspect of keeping any aquarium setup is ensuring the tank is properly “cycled” -- in other words, supports a healthy biome of beneficial bacteria to offset the biological wastes excreted by fish and microorganisms. This does not replace regular maintenance and the presence of sufficient filtration, but is potentially the biggest element in the health and wellbeing of your fish. You can read more about proper tank setup, water quality, and cycling here.
Goldfish are generally very hardy and can survive in a wide variety of extreme conditions in the wild, making them more forgiving of beginner fishkeepers’ mistakes. However, just because they CAN survive in less than ideal conditions, does not mean that they should be made to! Just like any other animal, goldfish have a preferred range of parameters in which they thrive, and every effort should be made to get as close to these ranges as possible. These freshwater fish prefer their water quite cool when compared to other commonly kept fishes, about 65-72 degrees. They are more tolerant of cooler water than warmer water. Generally, the room temperature of most peoples’ homes is sufficient and does not require any additional heat supplementation, but those in extremely hot areas may need to purchase a special chiller to maintain the correct water temperature. Goldfish prefer a pH between 7.2 to 7.6, but can acclimate to pH beyond this range, as long as it remains stable. They do not seem to be preferential to a particular water hardness, so long as it remains stable.
As a general rule, 20 gallons is the minimum acceptable tank size for short-bodied varieties, with 15 gallons per additional goldfish. For long-bodied varieties, 40 gallons per goldfish with an additional 20 gallons per additional fish is acceptable. As with any pet, take care to provide not just the “humane” minimum, but the largest size habitat you can afford to care for. Keeping goldfish in outdoor ponds is also an option, but care must be taken to both protect the pond from freezing and from potential predators that may view your pond fish as a quick and easy meal! Because these fish produce so much waste, heavy filtration is essential to the wellbeing of your aquarium. Fish waste can quickly turn into toxic chemical buildup, which can rapidly lead to illness and even death. Be sure to monitor your water values regularly with the use of a commercially-prepared water testing kit for freshwater fish.
SUBSTRATE
Goldfish are notorious for eating just about everything that can fit in their mouths (including other fish!), and with such a voracious appetite comes a lot of waste! This means that their tanks can become quite dirty very quickly! What does that mean for furnishing your tank? That depends on how much work you are committed to putting into your weekly maintenance. There are essentially two options -- traditional aquarium gravel/stones, or an entirely bare-bottom tank with no substrate. One option is not necessarily better than the other, it comes down entirely to personal preference. Many keepers house their goldfish on bare-bottom tanks, which makes your life easier when it’s time to clean the aquarium.
If you can’t bear the look of a plain glass bottom, traditional aquarium gravel is perfectly acceptable. Goldfish do seem to enjoy foraging around in the substrate for food scraps, as they would in the wild.
PLANTS AND GOLDFISH: YAY OR NAY?
If you love the look of a beautiful, lush, planted tank, goldfish may not be the best option for your aquarium -- being omnivorous little eating machines, they love to nibble on plants! This is not to say that you cannot have any plants at all in your aquarium -- quite the contrary. There are several hardy and relatively fast-growing aquarium plants that can stand up to the munching and digging habits of the goldfish, such as:
DIET
High quality flakes and sinking pellets labelled for goldfish are both appropriate, with Omega One being a reputable brand. Ideally, the food should provide about 30% protein for goldfish. However, pellets are generally more nutritionally stable for longer periods of time, simply due to their surface-to-mass ratio. “More expensive” does not necessarily equal “higher quality”, so take care to read the nutritional content on the label.
Occasionally, especially in community goldfish tanks, fish who are fed flakes can get what is known as “dropsy” -- this refers to huge volumes of air accumulating in the fish’s stomach, associated with voracious surface gulping at mealtime. This condition can create issues passing stool normally as well as buoyancy issues. Competition between other fish for flake food can contribute to this problem. A simple solution is simply choosing to feed sinking pellets. Goldfish are foragers by nature, so it may also provide enrichment for them to dig through the substrate to find pieces of food. Some keepers choose to offer both pellets and flakes. Ultimately, it is your choice, as long as your fish maintain good health.
HEALTH & BEHAVIORAL ISSUES
Many health issues present themselves as variances in behavior. Excellent husbandry and careful monitoring of water parameters will keep most illnesses from ever causing a problem for your fish. Some indicators of illness in your fish are:
Common issues we see in goldfish include proptosed eyes (eyes popped out of their socket), bacterial and fungal diseases, and both internal and external parasites, to name a few. You can read a comprehensive list of fish health concerns here. If you are ever concerned about your fish not acting well, please call us!
A NOTE ON INVASIVENESS
The goldfish has been documented in all lower 48 states, as a result of irresponsible dumping of pet fish into local waterways. Often, this occurs because that little goldfish Tommy won at the fair has now suddenly grown larger than expected. Other times, people move into new homes and decide not to take their fish with them. Unfortunately, they are extremely invasive. Goldfish, as previously stated, have voracious appetites for such small fish, creating huge amounts of waste and subsequently outcompeting local fauna. Over time, this can severely impact water quality for native fish species. Some research has shown that consumption of invasive goldfish can have adverse health effects on local carnivorous wildlife. If you are no longer able to care for your fish, please contact Chicago Exotics.
Our Phone number is 847-329-8709
(Carrasius auratus)
By Lindsay Mayer, Veterinary Assistant
NATURAL HISTORY
The goldfish is one of the most widely kept freshwater fish the world over. A domesticated descendant of the Koi, the goldfish has a long and storied past, originating in east Asia. This now massively popular fish originally farmed as food, its ancient ancestor was actually a silvery-gray color. This ancestor was known as “chi”. Occasionally, a vibrantly patterned or colored fish would be produced as a result of random genetic mutation. In the wild, these mutated goldfish would be eaten by predators. However, 9th century Chinese people began keeping these special “chi” fish in ponds, where they could be protected from predation (and becoming someone’s dinner!).
For a long time, these “goldfish” were unrecognizable from the silvery-gray wild fishes, and were wary of humans -- for about 100 years! So, how did the goldfish we know today come to be?
“In the Buddhist tradition, it is a good deed to set an animal free, especially if the animal is rare. So it became common practice throughout China for the rare coloured chi to be spared the stewpot and released into ponds. Official records document an accumulation of colourful chi in ponds around 975 CE.” (Goldman, 2014)
Eventually, both public ponds and those owned by the very wealthy began to explode with beautifully colored goldfishes. By 1240 CE, the goldfish had now become completely domesticated and separate from their chi ancestors, readily accepting of human interaction. At this point, there was no turning back -- people loved these brightly colored, interactive fish, and at once began selectively breeding to produce more and more varied breeds and colors.
These days, there are over 200 recognized breeds of goldfish available, but the vast majority available to the average pet owner fall under two categories: “common” or “single-tailed”, and “fancy” or “double-tailed” goldfish, with even more variations in body shapes and colors within each group. They can grow up to 12” in length (no, keeping them in a small tank will NOT stop them from growing!), and live between 5 and 30 years (the oldest ever recorded was 43!) depending on the breed. They are easily attainable, easy to keep, and long-lived. They have even been known to recognize and interact with their owners, making them an interesting aquatic housemate!
TANK SETUP & WATER QUALITY
With any aquarium setup, there are certain parameters that must be met, regardless of species. Perhaps the most important aspect of keeping any aquarium setup is ensuring the tank is properly “cycled” -- in other words, supports a healthy biome of beneficial bacteria to offset the biological wastes excreted by fish and microorganisms. This does not replace regular maintenance and the presence of sufficient filtration, but is potentially the biggest element in the health and wellbeing of your fish. You can read more about proper tank setup, water quality, and cycling here.
Goldfish are generally very hardy and can survive in a wide variety of extreme conditions in the wild, making them more forgiving of beginner fishkeepers’ mistakes. However, just because they CAN survive in less than ideal conditions, does not mean that they should be made to! Just like any other animal, goldfish have a preferred range of parameters in which they thrive, and every effort should be made to get as close to these ranges as possible. These freshwater fish prefer their water quite cool when compared to other commonly kept fishes, about 65-72 degrees. They are more tolerant of cooler water than warmer water. Generally, the room temperature of most peoples’ homes is sufficient and does not require any additional heat supplementation, but those in extremely hot areas may need to purchase a special chiller to maintain the correct water temperature. Goldfish prefer a pH between 7.2 to 7.6, but can acclimate to pH beyond this range, as long as it remains stable. They do not seem to be preferential to a particular water hardness, so long as it remains stable.
As a general rule, 20 gallons is the minimum acceptable tank size for short-bodied varieties, with 15 gallons per additional goldfish. For long-bodied varieties, 40 gallons per goldfish with an additional 20 gallons per additional fish is acceptable. As with any pet, take care to provide not just the “humane” minimum, but the largest size habitat you can afford to care for. Keeping goldfish in outdoor ponds is also an option, but care must be taken to both protect the pond from freezing and from potential predators that may view your pond fish as a quick and easy meal! Because these fish produce so much waste, heavy filtration is essential to the wellbeing of your aquarium. Fish waste can quickly turn into toxic chemical buildup, which can rapidly lead to illness and even death. Be sure to monitor your water values regularly with the use of a commercially-prepared water testing kit for freshwater fish.
SUBSTRATE
Goldfish are notorious for eating just about everything that can fit in their mouths (including other fish!), and with such a voracious appetite comes a lot of waste! This means that their tanks can become quite dirty very quickly! What does that mean for furnishing your tank? That depends on how much work you are committed to putting into your weekly maintenance. There are essentially two options -- traditional aquarium gravel/stones, or an entirely bare-bottom tank with no substrate. One option is not necessarily better than the other, it comes down entirely to personal preference. Many keepers house their goldfish on bare-bottom tanks, which makes your life easier when it’s time to clean the aquarium.
If you can’t bear the look of a plain glass bottom, traditional aquarium gravel is perfectly acceptable. Goldfish do seem to enjoy foraging around in the substrate for food scraps, as they would in the wild.
PLANTS AND GOLDFISH: YAY OR NAY?
If you love the look of a beautiful, lush, planted tank, goldfish may not be the best option for your aquarium -- being omnivorous little eating machines, they love to nibble on plants! This is not to say that you cannot have any plants at all in your aquarium -- quite the contrary. There are several hardy and relatively fast-growing aquarium plants that can stand up to the munching and digging habits of the goldfish, such as:
- Anubias
- Java Fern
- Cryptocoryne
- Vallisneria varieties
DIET
High quality flakes and sinking pellets labelled for goldfish are both appropriate, with Omega One being a reputable brand. Ideally, the food should provide about 30% protein for goldfish. However, pellets are generally more nutritionally stable for longer periods of time, simply due to their surface-to-mass ratio. “More expensive” does not necessarily equal “higher quality”, so take care to read the nutritional content on the label.
Occasionally, especially in community goldfish tanks, fish who are fed flakes can get what is known as “dropsy” -- this refers to huge volumes of air accumulating in the fish’s stomach, associated with voracious surface gulping at mealtime. This condition can create issues passing stool normally as well as buoyancy issues. Competition between other fish for flake food can contribute to this problem. A simple solution is simply choosing to feed sinking pellets. Goldfish are foragers by nature, so it may also provide enrichment for them to dig through the substrate to find pieces of food. Some keepers choose to offer both pellets and flakes. Ultimately, it is your choice, as long as your fish maintain good health.
HEALTH & BEHAVIORAL ISSUES
Many health issues present themselves as variances in behavior. Excellent husbandry and careful monitoring of water parameters will keep most illnesses from ever causing a problem for your fish. Some indicators of illness in your fish are:
- Swimming abnormally
- Floating at the surface or sinking to the bottom
- Lack of appetite
- Color appears washed out
- Fins appear ragged or torn
- Lethargy
Common issues we see in goldfish include proptosed eyes (eyes popped out of their socket), bacterial and fungal diseases, and both internal and external parasites, to name a few. You can read a comprehensive list of fish health concerns here. If you are ever concerned about your fish not acting well, please call us!
A NOTE ON INVASIVENESS
The goldfish has been documented in all lower 48 states, as a result of irresponsible dumping of pet fish into local waterways. Often, this occurs because that little goldfish Tommy won at the fair has now suddenly grown larger than expected. Other times, people move into new homes and decide not to take their fish with them. Unfortunately, they are extremely invasive. Goldfish, as previously stated, have voracious appetites for such small fish, creating huge amounts of waste and subsequently outcompeting local fauna. Over time, this can severely impact water quality for native fish species. Some research has shown that consumption of invasive goldfish can have adverse health effects on local carnivorous wildlife. If you are no longer able to care for your fish, please contact Chicago Exotics.
Our Phone number is 847-329-8709
