Goldfish: Characteristics, habitats, types and more…

Goldfish (Carassius auratus) belong to the cyprinids family. Don’t   miss this opportunity to know everything about these just striking fish.

These little angels can be obtained at any specialized pet store and you can distinguish between the around 125 existing varieties with variations of colors and shapes as a result of the crossing of different specimens.


Name: Goldfish Kingdom Animalia Phylum Chordata Class Actinopterygii  Order Cypriniformes Family Cyprinidae Genus Carassius Species C. AuratusGoldfish: Taxonomic classification

The Goldfish’ Origin

The origin of this species is not very clear. They might come from golden varieties of common carp (Carassius carassius) selected by man, or be a natural species. There are four subspecies described, all with brownish colorations and golden reflections, with enough chromatic variability.

The first ones that were dedicated to breed and reproduce these fish were the Chinese, around 1,000 years ago. At first, royalty alone was worthy of having a goldfish as a pet and could reproduce it with others.

The emperors and other royal members kept these animals in large ceramic containers, opting later for glass tanks that facilitated the vision of the beautiful colors of the fish. After a few years they introduced the goldfish into large ponds that also surrounded the royal gardens, which made it easier for them to breed.

Beginning in the 12th century, a more selective breeding began to develop, which gave rise to the different varieties of goldfish existing today differing in color, shape of eyes, fins and body.

Departure from China.

But the goldfish weren’t left alone in China. The Japanese immediately fell in love with these beautiful ornamental fish, so they began to raise them first in Koriyana, where they have not stopped working in this trade for more than 500 years, gaining great popularity all over the world.

The Japanese were the ones who developed the varieties of Shubunkin, Ryukin, Demekin, Tosakin, Jikin, Wakin and Hamanishiki.

By the 18th century, Japan’s commercial link and the export of ornamental fish were strengthened by countries such as England, Portugal, Holland and France. The goldfish became a “fashion item» becoming an ideal gift for any occasion.

At the end of the 19th century, the goldfish crossed the great sea, arriving in the United States where they gained much popularity. In this country, a new variety of fish that is considered 100% American would emerge: the comet fish.

At present, there are many breeders from different countries that still want to create new varieties of goldfish, but these new specimens may take some time to be recognized by the many societies of goldfish that exist in the world, since they are in charge of dictating the parameters to determine the quality of such specimens.




The Goldfish’ Main Characteristics

Goldfish are small fish, which reach a maximum of 60 cm in length and 3 kg in weight, although the specimens bred in aquariums seldom reach half this size. Their body is short and massive, with a scaless triangular-shaped head. Unlike other carps, goldfish lack scales in the upper jaw.

The dorsal fin is closed, with visible bony spines; the pelvic ones are short and wide, and the caudal one of big size after a short and wide peduncle. In the wild goldfish species, the body’s color varies from olive brown to yellowish white while the aquarium varieties are selected according to their xanthochromy, showing pigmentations ranging from intense golden yellow to red and purple.

let’s watch them

Types of Eyes According to the Species

Goldfish have different eyes shapes depending on the species. The most common or normal are those that are very similar to their ancestors ( the carps) and that are very similar to the eyes of most fish.

There are also telescope-type eyes whose pupil is protected by a protruding transparent cover. They are characterized by large protuberances so when they are in front they can be easily noticed. We invite you to read our article telescope eyes goldfish to learn about this interesting species.

The celestial type, are the eyes that are also projected towards the outside but unlike the previous ones the pupils are looking towards the top part. Finally, there is a variety of bubble eyes, which present a liquid sac under each eye, which is the reason for the origin of their name.

Types of Head According to the Species.

In the same way than their eyes, the different species of goldfish have different types of head depending on the specimen. The most common is the flat variety which is small and smooth and may be a little narrower or wider depending on the individual. However, this is the type of head that is considered normal, being so similar than that of other fish species.

The oranda variety, possess a sort of crown on the top of the head, as if it were an Afro. It is also worth mentioning the Cosetead in which the growth of this crown is more developed.

The Tigerhead or Lionhead specimens, have a head similar to the Cosetead, however their growth is more pronounced and covers the operculum and the lower part of the chin. This species has dorsal fin.

Types of scales according to the Species.

There is a type of scales that could be considered normal, since they are flat and is the type of skin that has most of the specimens of goldfish.

Other species have semi-spherical scales that project to the outside. Their main difference with normal ones is that they are harder, and if they fall they can grow again but not with the same shape, but flat.

Transparent scales have no pigment cells, which gives them this particular trait. Even in some cases they can show the animal’s organs.And finally there are the metallic scales that possess a very bright appearance, which makes the fish with them very rare and appreciated, especially if they have a warm color tint.

Types of tails according to the species

A long tail is presented in a double way and with a natural fall, occupying 2/3 parts of the total length of the fish, in the veil tail goldfish . Another type of tail similar, because it is also double, long and large is the Phoenix type; which belongs to a specimen of goldfish known by the same name (Phoenix), whose body is egg-shaped.

On the other hand, there is the type of simple tail belonging to the common goldfish as well as the distinctive «V» tail of comet fish.

The butterfly tail is double, medium size and with two large lobes, one on each side of the tail.  It is called in such a way due to its resemblance with butterflies when seen from the back being very common in the telescope eyes fish.

Another goldfish’s type of tail is the fan one, which is characterized by being double, short and fan-like. In English it is also known by the name of fantail. The variety goldfish called Jikin have a rather unique tail: the peacock tail, which is double and is raised and extended similar to a bird.

The last type of tail is the olan type, which is double but is joined with three lobes, two of which are bent backwards. This type of tail is exclusive of the Tosakin goldfish.

Let’s meet the stunning Tosaking Grooming

Golfish: Habitat and Feeding Patterns

Goldfish enjoy calm, warm waters, rich in vegetation and abundantly populated with tiny invertebrates, typically crustaceans such as earthworms, gammaras or red daphnia, to which they are amateurs.

In nature, goldfish feed consists of crustaceans, insects and their aquatic larvae, several crustaceans and several tender plants. Like most fish, they are opportunistic omnivores that don’t stop eating! As regards their diet in aquariums, their preferences vary according to each individual.

Good, artificial, crunchy or granular foods may be suitable for young goldfish fish less than 10 cm in length, but this food is becoming inappropriate for adult goldfish.

All dry foods for goldfish should be soaked before feeding. Avoid floating foods such as flakes or flakes as artificial foods.

Golden fish have a lower mouth that allows them to search for food from the ground, not from the surface.

How Do Goldfish Reproduce?

Their reproductive stage begins between the spring and summer seasons and it’s just at this time when the differences between males and females can be more easily distinguished.

During this stage the males usually present white spots in their gills that are known as nuptial efflorescences or sexual tubers, besides that their attitude toward the females changes, since the golden romeos usually persecute them insistently and hit their tubers or head against the females’ belly to incite them to untie the eggs.

On the other hand, the female acquire a more rounded body, especially between the ventral and anal fins, where the eggs spawning orifice is located.

Both males and females goldfish, have a single hole located in the back of their body, between the ventral and anal fins. Generally this orifice has the function of anus, but during the reproduction stage it is also used to excrete both the eggs and the necessary sperm.

In males, the hole is concave inward, while in females it is concave but outward.

Aquariums for Reproduction.

If you have decided to reproduce your goldfish you can choose one of these three grouping options. The first is to place a couple of male and female in a pond, you can put a trio consisting of two females and a male or in the case of having multiple specimens you can choose multiple pairs.

The couple reproduction method is the one that requires less space so it would be enough with a tank of 115 liters to house the individuals.

If you think of separating them from the rest of the fish, it is better to use an elongated and low-altitude aquarium, which allows you to handle the fish more easily, as well as facilitating their transfer. But you must bear in mind that you must have enough spaces where the female can take refuge from the male to rest.

Aquariums for New-born.

Many people who are dedicated to the breeding of goldfish, use some of these options for taking care of eggs. The first method, highly recommended if you have a pond on the floor or a huge aquarium, is to leave the eggs in the same tank where fertilization took place and only remove the parents.

Or you can choose to move the eggs to put them in one or more aquariums that will be the incubators. These tanks must be filled at the same time as the parents’ aquarium, in order to stabilize and adjust the water levels without affecting the development of the offspring.

The first option has the advantage that the fry won’t suffer from the stress generated by the transfer to another aquarium, however the parents’ aquarium is usually contaminated by excrement and decomposing sperm causing the levels of ammonia to rise up to affect to the newborn goldfish.

On the other hand the second option has the advantage that the water is cleaner and the eggs can be distributed in several aquariums. So if there is any disease not all the offspring will be lost; but in the process of transferring the eggs some can be lost when they become attached to plants, the glasses of the aquarium or between the filters.

An aquarium incubator with a capacity of approximately 75 liters of water, can hold an approximate of between 500 and 750 fertilized eggs.

Before the courtship.

Before inducing the goldfish reproduction process, it’s essential that they have a diet rich in nutrients to be strong. This way, the females will be able to release more fish and the males will be able to produce more sperm, thus increasing the fertilization rate. Similarly, the fry will be stronger leading to better development.

An ideal diet will be to offer our goldfish insect larva, small shrimp and as a complementary you can offer vegetables such as spinach, lettuce, peas chopped into 4 pieces and peas.

But for the spawning and subsequent fertilization to begin, it’s   necessary to make the goldfish feel the seasons of the year. In an aquarium where the temperature of the water remains stable throughout the year the fish don’t  go into heat, as the seasons go unnoticed.

We start with the end of autumn and the beginning of winter; for this, the temperature must be gradually reduced until reaching 10ºC, where it will remain stable for around 7 weeks.

We then go to the beginning of spring, for which we raise the temperature gradually until we reach 15ºC. After a couple of weeks we should continue to increase the temperature to 23ºC as if it were starting the summer.

Changes in temperature should be subtle, you should not go up or down more than 2 ° per day, because a very sudden change will cause the fish to become stressed and die.


When both females and males are sexually mature and ready to begin reproduction, they begin to swim in groups of 2 or 3 individuals, especially females.

It’s then when the males begin their harassment to make them separate from the group and direct them towards the plants.

Thanks to this initial ritual, the female can spawn the eggs, which the male will immediately proceed to fertilize by releasing sperm in turn.

Once outside, the eggs descend and adhere to the plants or any surface that is nearby, to remain motionless as they develop and the time of hatching arrives.

Special care should be taken that the aquarium or pond where our specimens of goldfish are, has enough plants and hiding places, since courtship can generate a lot of stress on the female, and if she isn’t able to escape to rest she could die.

Generally, the goldfish’ reproduction processes occur during the early morning, and can last for one or even several days.

A single female is able to release between 5,000 and 10,000 eggs in a single laying, but not all will be reached by the sperm to be fertilized, they could even be eaten by parents or other fish if they are not separated in a prudent time.

Eggs and offspring development.

When they have been fertilized, the eggs get an opaque yellow coloration.. On the other hand, the eggs that were not fertilized become white and opaque only 24 hours after being expelled; if they are not removed from the aquarium they will be filled with fungi, which can bring infections and diseases to the rest of the inhabitants.

After only 2 or 3 days of being fertilized inside the egg you can see small eyes, as well as a latent heart, which is sure if it is the first time that the time impressed you and filled you with emotion.

For the 5th or 7th day of development, the egg is finally opened so that the embryo can leave, however it will not have mobility and will not be able to swim easily, so it will remain around 2 more days in a resting state and can begin to swim to look for food.

After a month, the small fry already begin to acquire the general appearance of an adult gold fish. First the body is covered with scales, since until now it had a transparent body; the fins develop and the coloration of the fish begins, and can change in the next 3 years when it acquires its final color.

Feeding the young goldfish.

Once they are born, it is important to provide the fry with a rich and varied diet,  so that they can grow healthy and strong. A good option for the first days of life is to offer cooked and ground egg yolk, although it should be done in small portions to avoid the aquarium water getting too dirty. Another good option is to offer small pieces of commercial flakes.

They can also be fed live food such as baby shrimp, earthworms, tubifex and bloodworm, previously ground to a mush. It can be a bit difficult and expensive but a specialized commercial feed for fingerlings can provide the necessary nutrients for them.

There are some breeders who prefer not to use live feed for fear of introducing some fungus or infection that could be fatal to the health of the small fry.

The first weeks of life require a constant feeding, between 3 to 6 times a days at regular intervals in the morning, afternoon and evening.

If you feed the young goldfish at night, you should turn on a dim light, because their vision is quite limited and without it they could not find the food.

As a final recommendation, it is important to clean the water after each meal so that it does not become contaminated and may affect the young.

Infusions for fingerlings.

Among the goldfish breeders, a method has been popularized to feed the fry that is very easy and nutritious: an infusion that provides many proteins and can be prepared at home.

First it must be filled with water, previously boiled and left to cool, three quarters of a jar or container. Inside, a banana or banana peel is placed or 3 or 4 leaves of lettuce, preferably external and battered, can also be used. The jar should be left without a lid in a sunny place but it should be

Leave the jug without lid in a sunny place but outside the house, its smell will become stronger and more unbearable.

After a few days the water will become cloudy and will have a very stinky aroma. After two days the water tone will change becoming clearer; In spite of its smell it will be equally stinking, it will have a slight sweetness easy to perceive.

Add the infusion to the aquarium water using a turkey filler or spoon. This mixture can last for up to 3 days, so to feed the fry in this way a new preparation should be done every 2 or 3 days.

Let’s watch how they mate


How to take care of Goldfish in Captivity?

For optimal development each adult specimen merits an aquarium with a minimum capacity of 37 liters of water or more. With this the myth that goldfish can be kept in round and small fish tanks as many times seen on television is disproved. With this type of captivity only the fish gets sick and dies little by little, since they don’t have an adequate place to grow and swim.

All the varieties of goldfish are characterized by a fairly peaceful behavior, being able to live with fish of the same species or other types of specimens.

Which Fish are Compatible with Goldfish?

The fish compatible with goldfish are: rotengles, tenches, koi, Corydora paleatus, Chinese Neons which require specialized care. Snails such as ramshorn and apple snail are useful in eating any algae while remaining safe for aquatic plants. But if there is no control over the fish population, the ponds can easily fill up and overpopulate.

How much does a goldfish live?

The goldfish life expectancy in captivity is at least 10 years in a sufficiently spacious aquarium, but the usual duration is 15 years. The smaller the aquarium, the shorter the duration (less than 5 years).

On the contrary, the higher the volume the greater the increase in this period (from 20 to 25 years). To date, the life expectancy of a goldfish has been about 43 years.

let’s meet these stunning fish called angels koi

Popular species of Golfish

As stated above, there are many varieties of these beautiful fish currently collecting about 125. However among the most popular specimens we can highlight three types.

Comet fish

It was created in the United States approximately in the year 1880, shortly after the arrival of the goldfish to America. It differs from many of the members of his family by having a longer and more elegant body in addition to having more developed fins having a slightly pointed shape at the ends, as well as having only one tail fin. They can be found in various colors that vary in white, silver, yellow and some red colors. Another feature is that they are very good swimmers and very agile.

Koi fish.

These are the specimens of goldfish par excellence, being adaptable to many environments and water conditions, so they are highly recommended for aquarium beginners.

They come from Japan, where the word koi means love or affection. The koi fish breeding grew so important that in the early twentieth century Japanese koi fish ponds became very popular, they even have a legend that is based on their beauty and virtues. In many countries, outside the Asian continent, the figure of breeder of orange fish or professional golden carp has become common.

Oranda fish.

This species arose in China and Japan approximately in the years 1590, when its breeding and crossing of species began. In the Chinese Empire and even today it is known as «The Flower of Water». It has a long and deep body presenting a wide belly. Its dorsal fin is large and elegant, while its tail is fourfold. A special feature is its cap or crown that grows on the top of its head with a rough appearance, which suggests an afro of the 80s.

Let’s meet them


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