Goldfish

a bright orange goldfish with air bubbles all around them

Goldfish are a popular choice for a fish, and for good reason. They’re relatively low maintenance, easy to care for, and can bring a lot of joy to their owners. If you’re considering getting a goldfish as your first fish, you’ve come to the right place!

Goldfish are members of the carp family and have been kept as pets for centuries. They come in a variety of shapes, sizes, and colors, so you’re sure to find one that fits your personality. Goldfish can live up to 15 years if properly cared for, so they make a great long-term fish.

When it comes to care, goldfish are somewhat low maintenance. They require a tank of at least 20 gallons with a filter and heater. The water should be changed regularly and the tank should be cleaned every two weeks. Goldfish also need plenty of oxygen, so an air pump is recommended.

Goldfish are small fish that come in a variety of colors and patterns. They are commonly kept in aquariums, ponds, and fishbowls. They are very friendly but not so easy to care for. Because they release a higher bio load in the water, more attention is needed to keep the dissolved toxins down.

Goldfish are typically very peaceful and docile, and will generally avoid getting into fights with other fish. 

Goldfish can be great fish for your aquarium because they have a long lifespan of 15 years, they are easy to look after, and they are cheap to buy! Young goldfish are especially easy to look after, and they come in so many different colors! They also get along with many different types of fish so you don’t need to worry much about them fighting.

They are also fairly inexpensive, usually costing between $4 and $6 per Goldfish.

Goldfish are omnivores, so they need a variety of food. A good diet for goldfish consists of high-quality flakes or pellets, frozen or freeze-dried foods, and live foods such as brine shrimp or bloodworms. It’s important to feed your goldfish in moderation and avoid overfeeding them.

Goldfish are an ideal pet for first time owners. They’re easy to care for and make great family pets. With the right care and diet, your goldfish will bring you years of enjoyment!

Goldfish Information

  • Average Length: 4 to 12 inches depending on variety
  • Average Weight: 8 to 12 ounces 
  • Scale Appearance: Translucent
  • Colors: Orange, red, golden, blue
  • Attention Requirements: Low
  • Tolerance to Heat and Cold: Yes
  • Good Pet: Yes!
  • Good with Other fish species: Yes 
  • Good with Other Goldfish: Yes
  • Suitable to live in an Apartment: Yes
  • Good for Less Experienced Pet Owners: No
  • Training: They can learn a few tricks 
  • Weight Gain: Can become overweight if overfed
  • Health Concerns: Swim bladder problems, complications when ammonia levels are high, and death due to drastic water changes.
  • Average Life Span: 10 – 15 years

Physical Appearance of Goldfish

Goldfish can be many different colors, but orange and red are the most common colors. The original Goldfish from China had a golden color but after many years of selective breeding in domestication, there are now many gene mutations. The gene mutations have created a much more diverse color range for Goldfish.

Wild Goldfish have only one scale type while the domesticated varieties have three scale variations. Goldfish have pigment cells called chromatophores which determine the color variation of your pet. 

Goldfish have guanine chemical deposits on their skin which cause the shiny reflective colors you see on them. You probably didn’t know but Goldfish scales are thin, translucent and colorless. Their color depends on the amount of guanine in their skin and how deep it’s deposited.

Goldfish are also known to change their color’s brightness depending on the amount of light available. Many people that own them say that if you turn off the lights at night, the following morning your fish will appear pale or dull. This is interesting because Goldfish kept in a pond outdoors appear brighter than the fish kept indoors.

There are 3 scale types for Goldfish.

Matte

This scale type has a translucent color without any reflection.

Metallic

Metallic scale types have a translucent and reflective look. The scales look like polished metal. These Goldfish have one or two color variations depending on their genetic makeup. Most Goldfish have this type of scale.

Nacreous

These types of scales have a combination of reflecting and translucent skin. Most Goldfish in this category have more than one color variation of orange, red, blue, and white.

Temperament of Goldfish

Goldfish are peaceful and easy going, but just like other fish, they can become aggressive if they don’t feel safe in their home.

They can fight each other for space if more than one are kept in a small tank. Goldfish love swimming in large tanks and playing with the sand. In a smaller tank without a lot of space, they can become stressed and aggressive.

Another reason that can cause Goldfish to become aggressive is breeding. Male Goldfish are known to be violent during the breeding season. They may also fight for eggs in the aquarium because goldfish love eating their eggs before hatching.

How can you detect signs of an aggressive Goldfish in your aquarium? Here are some of the things to look out for:

  • Fish with missing scales
  • Goldfish with torn lips or fins
  • Signs of rotting on the bodies of fish
  • Missing eyes
  • Fish hiding for a long periods of time

Tank Conditions for Goldfish

Goldfish do alright in cold water but they do tend to do much better with warmer temperatures. For Goldfish cold water is between 65 and 72 degrees Fahrenheit and warmer is between 68 and 74 degrees. If your home temperature is between 65 and 72 degrees Fahrenheit, you don’t need a water heater for their aquarium unless you have other fish with them.  

The best pH for your Goldfish is between 7.0 and 7.4 with slightly alkaline water.

Tank Maintenance

The temperature and pH level inside the tank should be checked regularly. Rapid changes with temperature or water quality can be harmful to all of your fish. 

A good filtration system should also be used inside the tank. Around 10% of the water should be replaced every week. If you miss a week, then a 25% water change should be done the following week. If you are using tap water, make sure to treat it with a water conditioner to neutralize the chlorine.  

The level of compounds like ammonia, nitrate and nitrite should be checked regularly. The quantity and frequency of water changes will depend upon the number of fish, the size of the tank and if your fish are overfed.

Best Tank Mates for Goldfish

There are a few concerns for selecting a tank mate for your Goldfish. They must be comfortable in the same temperatures that the Goldfish needs. Goldfish generally like to live alone and most Goldfish who have been alone for a year may not like any company. A good start would be to add another Goldfish. 

Another concern is that they can be aggressive towards other Goldfish. If you plan to keep multiple Goldfish together it is best if they are close to the same size, otherwise the larger ones might bully the smaller ones. The tank size should also be large enough that they have enough space. Experts recommend having 20 gallons of water for one Goldfish and adding 10 gallons for each additional goldfish.

Some of the best tank mates for Goldfish are:

Health Issues

Goldfish can contract illnesses from their environment fairly easily. Here are some of the reasons why your pet could get sick or die.

High levels of Ammonia in the Water

Ammonia is a chemical compound that can be found in freshwater fish tanks, and it is toxic to the fish if not monitored and controlled. High levels of ammonia in the water can cause serious health problems for your fish, leading to death if left untreated. It’s important to monitor the ammonia levels of your tank regularly to ensure that your fish are safe and healthy.

Dry Swim Bladder

Dry Swim Bladder is a common condition in aquarium-kept fish. The swim bladder is an organ that helps maintain buoyancy and balance within the fish’s body, and when it becomes dry this can cause a fish to become unbalanced or unable to stay afloat. Constipation can occur when the digestive system slows down, resulting in a build- up of mucus or feces in their intestines and causing further imbalances. As a result, the fish can become listless, float erratically, or have signs of stress such as gasping for air.

General Goldfish Care

A Goldfish will live for many years if the right water conditions are maintained in their tank. A sudden change in water temperatures can shock your fish and kill them. 

Always have water testing kits to ensure that the water conditions remain constant. 

Goldfish release waste at a higher rate compared to other types of fish. The waste can quickly kill your fish if not dealt with promptly. We recommend having a large tank for your fish to reduce problems with their higher waste load. A larger aquarium can diffuse the toxic chemicals into more water, making it easier to keep the bio load in balance.

Attention Needs of Goldfish

For many children, Goldfish will be their first pet, but they aren’t the best choice for beginners. They need large 20 to 30 gallons tanks as a safe minimum size. 

For every additional fish you place in the tank, we highly recommend adding 10 gallons of water. Remember the bigger the aquarium size, the more expensive they get. It’s extremely important that Goldfish owners have good filtration systems to help remove the harmful chemicals.

Not having a good, or even any type of filtration system is the #1 reason why Goldfish tend to die within a week. Filters keep a safe environment for the fish tank by removing some of the toxic chemicals. If you’re a beginner, it’s very easy to make mistakes that can lead to the death of your fish within days.

Feeding Goldfish

Goldfish are omnivorous and will eat commercial pellets available at all the pet stores. As you feed your Goldfish commercial pellets, experts recommend soaking the pellets in some aquarium water before feeding it to them. Soaking the pellets in some aquarium water minimizes the chances that your fish will have dried swim bladder problems.

Some will also eat live foods such as bloodworms, insects, and some very finely shredded vegetables. Quite often a local pet store will have live food for your fish if you want to feed them something different from their usual fish flakes.

It’s also worth noting that Goldfish should only be fed twice a day. Because they have very small stomachs, only feed them what they can eat within 3 to 5 minutes. Overfeeding your fish could result in abdominal problems. Leftover fish food will contaminate the tank and create higher levels of ammonia as it decays.

Sprinkle the flakes and pellets onto the surface of the water.  Your fish will eat them right at the surface. 

Related Questions:

Can I Have More than One Goldfish in a Tank?

The general rule of thumb when keeping more than one Goldfish in a tank is all about the size of the tank. Having to place a single or two goldfish in a 20 gallon tank seems as though the tank is empty but is beneficial to your pets. If you have a smaller tank and want it to look more full then other fish might be better for your family.

Goldfish exist in different varieties, when placing them together in a tank you should observe their fins. Goldfish that have similar fins are compatible and can coexist peacefully but generally all goldfish varieties can live together.

Some goldfish varieties such as the Lionhead, Bubblehead, and Ranchu have double fins which are bulkier making them slower. Single finned Goldfish such as the Comet are fast swimmers. Placing a faster and a slower goldfish together could lead to competition for food.

Are Goldfish Good with Other Fish Species?

It’s possible to place your Goldfish with other fish species as long as you make sure they can all survive in similar water conditions. You also have to ensure that the fish are compatible so they won’t get aggressive with each other.

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Contributing Author & Social Media Expert

Maryna is an animal expert that has had dozens of animals in her life over the years. She has never found an animal that she didn't love immediately. It seems like every year she finds kittens that have been abandoned by their mom and she nurses them to health and finds homes for them. She contributes her vast knowledge about animals and family pets to our website and we're forever grateful to have her working with us. She's also an amazing graphics designer and has designed all of the social media images that we use across all platforms.