Con cá
Con cá
HomeFreshwater FishCommon Goldfish: Size, Lifespan, Care & Tank Mates

Common Goldfish: Size, Lifespan, Care & Tank Mates

Common Goldfish, which are genetically identical to fancy goldfish but lack the distinctive shapes, morphologies, and fin patterns of their counterparts, have a rich history as one of the oldest pet fish. Despite their simplicity in appearance, they remain a beloved choice for fish enthusiasts worldwide. These goldfish can thrive as pets and coexist peacefully with other non-aggressive fish. They possess an endearing quality of playfulness and can even develop the ability to recognize their primary caregiver, often exhibiting eager anticipation at mealtime by gathering at the top or front of their tank.

Continue reading to discover more about the delightful and unassuming Common Goldfish.

Quick Facts about Common Goldfish

For those delving into the world of aquatic pets, the Common Goldfish, scientifically named Carassius auratus, stands out as an iconic choice. Hailing from the Cyprinidae family, this species is not only delightful to watch but is also fairly easy to care for, making it perfect for both novice and seasoned fishkeepers.

Aspect  Details 
Species  Common Goldfish (Carassius auratus) 
Family  Cyprinidae 
Temperature Range  20°C (68°F) to 22°C (72°F) 
Personality Traits  Peaceful and social, interacts well with tank mates 
Color Palette  Shades of orange, white, yellow, with combinations like red and white, black and red, or yellow and black 
Lifespan  15 to 20 years with proper care 
Size  Adult: 6 to 12 inches 
Diet  Balanced diet including pellets, flakes, gel food, occasional live/frozen treats, and roughage 
Ideal Tank Size  Juveniles: 55-gallon tank; Adults: 75 gallons or more 
Tank Setup  Good filtration, bare bottom or substrate (sand/rocks), goldfish-friendly plants, smooth decor 
Tank Mates  Get along with other Common Goldfish; can cohabitate with Comet goldfish or Koi in larger setups 

Common Goldfish Overview

Common Goldfish are an excellent choice for novice fishkeepers because they have readily available food and care supplies. Contrary to a common misconception, they are capable of living long lives, reaching up to 20 years or even longer with proper water quality and a suitable diet. In fact, the oldest recorded common goldfish lived an impressive 43 years!

These goldfish exhibit a wide range of colors, and although their most prevalent orange-gold hue may initially appear unremarkable, observing their iridescent scales darting through an aquarium can be visually captivating.

Common Goldfish Overview
Common Goldfish Overview

Common Goldfish can thrive in both indoor aquariums and outdoor ponds. In their natural habitat, their wild carp relatives endure cold temperatures during winter, allowing common goldfish in ponds to withstand water as cold as 32 – 40˚F (0 – 4.4˚C).

They adapt well to various aquarium or pond setups as long as they receive regular water changes along with appropriate toxin-removing treatments. Additionally, they require a high-quality and diverse diet, as well as a stimulating environment that can include tank mates, plants, and decorations.

Being natural foragers, Common Goldfish benefit from having roughage to graze on. They enjoy consuming items such as duckweed, cucumber, and live food. While they may occasionally nibble on aquarium plants, they typically leave plants like anubias, java fern, and hornwort untouched.

Appearance and behavior of Common Goldfish

The allure of Common Goldfish lies in their vivid and captivating shades, with a palette ranging from fiery orange and red to mellow yellow, earthy grey, and deep black. Their elongated bodies, often recognized by their common goldfish size, are complemented by gracefully arching dorsal fins, and a distinguishing stripe runs across their belly, adding to their visual charm.

However, these bright colors can easily dim under stress. Factors like antagonistic tankmates, sub-par water quality, and cramped living spaces can sap their vibrancy, making them appear more muted.

Appearance and behavior of Common Goldfish
Appearance and behavior of Common Goldfish

Differentiating between male and female can be a tad tricky. During mating seasons, keen observers can spot males showcasing dots on their gills and fins, which serves as an identification marker for their gender.

The size of a Common Goldfish is intrinsically tied to its habitat. While the more expansive tanks allow them to grow grander, a confined space might stunt their growth. It’s recommended for indoor goldfish enthusiasts to provide at least a 20-gallon tank for these fish to thrive.

For those with a penchant for outdoor ponds, it’s worth noting that Common Goldfish not only tend to live longer in these environments but also attain a larger size, with some reaching an impressive 12 inches in length.

How to Take Care of Common Goldfish

Owning a goldfish isn’t just about having a pet; it’s about creating a conducive environment for them to thrive. Here’s your goldfish care guide to ensure your goldfish gets the best care:

Take Care of Common Goldfish
Take Care of Common Goldfish

Tank/Aquarium Size

For a single adult Common Goldfish, an aquarium size of at least 55 gallons is mandatory. This is what we call the common goldfish tank size. However, goldfish are social creatures. If you’re planning on keeping a pair, aim for a 70 to 75-gallon aquarium. A spacious pond, accommodating groups of 5 or more, makes for an ideal habitat for these aquatic beings.

Water Temperature

Common Goldfish are fairly adaptable to temperature ranges, comfortably swimming between 16–22°C (60.8 – 71.6°F). Remarkably resilient, they can withstand icy chills, provided there’s a hole in the frozen surface ensuring oxygen supply. However, juvenile goldfish are more susceptible to cold, and it’s advised against placing them in freezing ponds.

In cold water, usually around 40º F, goldfish enter a phase of semi-hibernation, known as torpor. Here, their metabolic rate drops, and their appetite dwindles. While they can bear some heat, temperatures soaring above 86 °F (30 °C) could be detrimental. An optimal pH of 7.0 ensures a safe and healthy environment, though they can adapt to slight deviations.


It is generally advised against using small gravel for goldfish tanks since larger pieces can potentially get stuck in their mouths. Some goldfish keepers prefer a bare bottom setup for easy cleaning, but aquarium sand is also a suitable option. If purchased river rocks are used in indoor or outdoor setups, they should be thoroughly rinsed beforehand and should have smooth surfaces without any sharp edges to avoid injuring the fish. It is crucial to avoid sourcing rocks or plants from local waterways to prevent the transmission of parasites and diseases.

Take Care of Common Goldfish 2
Take Care of Common Goldfish 2


Goldfish are unlikely to consume plants such as anubias, java ferns, hornwort, moneywort, and Amazon swords. Instead, they tend to prefer plants like duckweed, frogbit, and salvinia. Additionally, certain plants can be cultivated to grow from the water’s surface, such as pothos, tradescantia, and bamboo.


Goldfish aren’t nocturnal and do need their daily dose of light. Avoid placing their tank under direct sunlight to deter algae growth. For indoor setups, artificial lighting works wonders. But remember, just as we need our rest, so do they. Ensure to turn off the lights periodically, simulating natural day-night cycles.


Ensuring your tank’s water remains pristine is pivotal. Filters are crucial, removing larger impurities like food residues and waste. Beyond just physical cleaning, filters also foster the growth of beneficial bacteria, crucial for neutralizing ammonia and managing nitrogen. Additionally, some filters are equipped with chemical filtration capabilities, further purifying the water by neutralizing toxins.

Are Common Goldfish Good Tank Mates?

When it comes to sharing their aquatic abode, Common Goldfish have particular preferences. Ideally, their best companions are, well, their own kind. These friendly swimmers are most content when housed alongside other common goldfish.

If you’re looking to mix things up a bit, Comets, Shubunkins, and Koi fish can be considered. However, remember, Koi especially can grow considerably large, so you’ll need a sizable pond to ensure all residents have ample room to glide gracefully.

But a word of caution: it’s tempting to introduce tropical fish to the mix, given their vibrant hues and patterns. However, this isn’t advisable. Tropical fish thrive at different temperature ranges compared to goldfish.

Common Goldfish Good Tank Mates
Common Goldfish Good Tank Mates


When adult goldfish are subjected to prolonged periods of cold water, inducing torpor, they often exhibit spawning behavior upon being reintroduced to warmer water. To enhance the chances of successful egg fertilization, it is recommended to maintain a male to female ratio of 3:1 during breeding. Gradually increasing the duration of light exposure, typically reaching 14-16 hours per day in indoor settings, is also advised. In order to stimulate egg production, it may be necessary to augment the feeding regimen.

To safeguard the fertilized eggs from being consumed, it is advisable to transfer them to a separate tank. It is highly likely that any surviving fry would be preyed upon by the adult fish.


How Much Do Common Goldfish Cost?

While Common Goldfish themselves are relatively affordable, with prices typically ranging from under $1 at most local pet stores to $10 or more when purchased from online retailers, it’s essential to consider the bigger picture. The cost of the fish is just a fraction of what’s required to provide them with a suitable home.

The real investment begins with setting up the perfect environment for these aquatic beauties. Remember, the upfront cost of the aquarium, essential accessories, food, a water testing kit, and vital water treatments can quickly add up. A basic aquarium setup for a pair of common goldfish can start around $150. However, if you’re envisioning a more expansive and elaborate aquarium with superior filtration systems, be prepared to invest several hundred dollars more.

Common Goldfish Price
Common Goldfish Price


Diving into the world of Common Goldfish, one quickly realizes the depth and intricacy of these seemingly straightforward creatures.

Their care, while demanding certain attention to detail, offers immense rewards, making them an ideal companion for aquatic enthusiasts of all experience levels. Their vivid colors and engaging personalities make them a delightful centerpiece in any home aquarium or garden pond.

For any fish keeper, experimenting with their diet, observing their behaviors, and understanding their personalities can be a captivating journey. Remember, a commitment to a Common Goldfish isn’t a fleeting decision.

These vibrant swimmers can grace your home for over a decade, offering joy and serenity. It’s imperative to approach their care with respect, understanding, and a genuine desire to ensure their well-being.

For more captivating tales and expert advice from the deep, don’t hesitate to explore further with DryWashAquarium. Dive into our other blogs and let your aquatic passion flourish!

See More:

  1. Butterfly Goldfish: Size, Lifespan, Care & Tank Mates
  2. Fantail Goldfish: Size, Lifespan, Care & Tank Mates
  3. Ryukin Goldfish: Size, Lifespan, Care & Tank Mates
  4. Shubunkin Goldfish: Size, Lifespan, Care & Tank Mates
5/5 - (1 vote)
Mark Senske
Mark Senske
Mark Senske is a highly regarded expert in freshwater and marine aquascaping, specializing in creating captivating and visually striking aquariums. With his extensive knowledge and experience, he excels in designing and maintaining beautiful aquatic environments that showcase the natural beauty of fish and plants.


Please enter your comment!
Please enter your name here

Most Popular

Recent Comments