Veiltail fish: Characteristics, reproduction, care and more….

The veiltail fish  or betta veiltail  is a type of golden fish (Carassius auratus ) that is a must-have for any eyes-catching aquarium. Join us to learn everything about them.


Phylum: Chordata  Class: Actinopterygii  Order: Cypriniformes Family: Cyprinidae Genus: Carassius Species: C. auratus

The Veiltail Fish’ Main Characteristics

Their body is shortened, plump and not at all rough although they have a very subtle and elegant appearance. In addition, their rear fin usually bifurcates ending in a small tip. It shouldn´t be rigid at any time, should bend downward and measure almost three quarters of the length of the fish, in healthy and good quality  specimens.

The remaining fins must be paired two in two excepting the dorsal fin, which also should look very rigid. Veiltail fish adult specimens measure between 10 and 15 centimeters, with the female always being somewhat larger than the males. We invite you to read our article the anatomy of fish to learn more about this topic

Veiltail fish’ Common Coloration

These fish are characterized by a very bright and intense color. The orange is almost always the predominating color, although many specimens have also white, blue and red hues.

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How to Feed Veiltail Fish?

Their diet should vary according to the season of the year, since during summer their appetite is greater than during winter. Like most Goldfish, veiltail fish eat almost everything you provide them, so you must take special care of binge eating that can adversely affect their digestive system.

This appetite is beneficial because they can eat in different ways, so you can give them both live food (which will help them to have more proteins for their growth), as well as fiber and hydrates with vegetable preparations, fruits and other vegetables that will prevent the arising of diseases on their swim bladder.

How Do Veiltail Fish Reproduce?

Breeding veiltail fish is a task that takes time and costs money. You will probably need an additional aquarium, since fry can´t be raised in the parents ‘one. However if you want to try, we indicate following the main aspects you should consider.

Find out the sex

Determining the sex of veiltail fish when they are less than one year old, is not an easy task. However, there are certain aspects that will be useful for this purpose, which accentuate when they reach sexual maturity.

First:  Males are easy to identify when they are ready to reproduce, since they develop a white spot on their gills and pectoral fins. These white dots look like grains of salt and can be detected in males from 8 months old.

Second:  Another way to determine the sex of the veiltail fish is by courtship. The male is insistent, hitting his head lightly and insistently against the female´s abdomen. The Courtship can last hours or even days, at the end of which the female can be exhausted and stressed. The males can be so insistent that they can kill the female if she can´t get away and rest.

The persecution has only one objective: to stimulate the female to release the eggs that the male will later fertilize by spraying the sperm on them. It may be the case that two males or more fecundate the eggs.

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Third: Males and females have a single hole, which fulfills the function of both the anus and reproductive system. The shape of such hole is different in males and females. It´s orifice concave inward in males, while in the female it´s concave outward.


Fourth: Healthy-looking adult females tend to be fatter and broader than males, while the latter are more slender in the abdomen area

Parents Selection

The quality of the breeding will depend on the parents. It´s recommended that they be between 2 and 4 years old. Younger fish produce smaller eggs, which will reduce the chances of fertilization. Older fish produce more eggs, which are often larger and more fertile.

Aquariums and Accessories

The size of the aquarium for reproduction varies according to: the number of fish, the type of veiltail fish and their size. There are three ways to make up the parent groups: in pairs, trios and multiples.

The first one requires less space. The ideal aquarium should have at least 30 gallons of capacity, being elongated and  low in height. Sometimes veiltail fish are bred in smaller aquariums, which is not advisable since it jeopardizes the female´s health and life.

In the trio reproduction, two males and one female are used, and a bit more space is required. For most medium-sized varieties, a 30-gallon aquarium is will be enough.

In the third method known as multiple, many males and females are used. It´s  recommended that the number of males be twice that of females. This method requires much more space than the previous ones, and is usually carried out in ponds built for this purpose. This method is quite effective for obtaining good quality specimens, since it increases the number of crosses.

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Recommended Filtration:

Two large filter box, power head or/and plate filter. The box filters are extracted when the fry are born in case they are not moved to the incubator Aquarium.

Incubator Aquarium

There are two methods for eggs care. One is to leave them in the parents aquarium  (not without first remove the parents), keeping them there until the tenth day of birth, when they are selected discarding the defective specimens.

In the second method the fertilized eggs are removed and transferred to an incubator Aquarium. In this method some eggs are lost that are adhered to plants, the glass and even the filter.

The benefits of the second method are two: fertilized eggs can be placed in various aquariums. The reason why some breeders do so, is that in case of diseases appearance not all eggs will be lost, but only those found in the affected aquarium. The second benefit is that the water will be cleaner and free of the parent’s aquarium characteristic contamination.

Steps to follow before courtship

A nutrient-rich diet is recommended for parents, since they will be strong, healthy and easier to reproduce. Recommended High Protein Foods:  «bloodworm «, insect larvae, small shrimp, etc. On the other hand, it will be necessary to include vegetable protein such as spinach, lettuce and peas.

Another important aspect that shouldn´t  be forgotten is to introduce plants in the aquarium. They must be leafy in order to provide refuge to fertilized eggs. The veiltail fish reproduce with relative ease in ponds, since their reproductive cycle follows the seasons of the year.

In an aquarium where the water temperature remains stable throughout the year, the veiltail fish don´t go into «zeal», as the seasons of the year are unnoticed for them. That’s why they require our “help «.

The aquarium temperature should be gradually decreased and over several days, as if it were the beginning of autumn and winter. Moreover, the parents should stay in an aquarium at a temperature of 10 degrees C for 7 weeks. After this, the temperature should be raised gradually up to 15ºC, thus simulating the beginning of spring.

A couple of weeks later you must increase the temperature gradually up to 23ºC, as if it were the beginning of the summer. Once this is done the fish should start the courtship. It´s important to make the temperature changes gradually, i.e. not going up/down more than 2ºC per day, since sudden changes could be very harmful.


When fish are ready for reproduction, you’ll notice they start swimming in groups of 2 or 3. It´s then when the males start chasing and harassing the females, separated them from the rest of the group and conduct them insistently towards the plants. It´s based on this courtship that the female expels the eggs and then the male releases his sperm to fertilize them.

The eggs descend and adhere to the plants and other adjacent surfaces, where they will remain motionless until the fry are born. A female can easily drop between 5.000 and 10.000 eggs in a single laying, but a large number of them won´t be fertilized or will be devoured by parents if they are not separated on time.

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Eggs Development and Birth

The fertilized eggs have an opaque yellow tone. The unfertilized ones usually acquire an opaque white tone since they are covered with fungi, so they must be extracted from the aquarium.

After 2-3 days of being fertilized their eyes and latent heart are easy to distinguish. They start moving  in the fifth day when the embryo pigmentation is clearly appreciated. Between the fifth and seventh day the egg opens and the embryo comes out with ease to mobilize but not for swimming so they´ll will spend most of the time resting.

It’s going to be two more days before they start swimming in search of food. One month after birth, the fry start looking like an adult specimen. Their body is covered with scales, their fins begin to develop and their coloring changes begin, and will continue during the first 3 years of their life.

Offspring Care

The First 12 days of life

In this time interval the juvenile veiltail fish can live and grow without any problem, in a slightly overpopulated aquarium.  Such fact makes it easier for them to find the food. It´s necessary to make daily water changes, as well as maintaining a good filtration and aeration. Growth occurs very quickly and up to 500 fry can share a 20-gallon shallow aquarium.

After the first 12 Days of Life

12 days after the fry leave the egg the first selection must be carried out, eliminating the specimens that show visible defects: deformed body, weakness, poor coloration, lack of fins, inadequate head, among others. When fry reach four weeks of age, they should be kept at a density of 30 fry per 144 square inches of surface area. At eight weeks of age they should be kept at the same density as an adult specimen.

Failure to make a selection and elimination of defective fry, keeping their numbers low as they grow, diseases will take care of doing so. This makes the difference between breeding quality specimens and specimens that were lucky to survive.

Feeding the Fry

The fry require a rich and varied diet to grow strong and healthy. During the first few days in particular, it´s  recommended to boil the eggs until they harden, and feed them the previously ground yolk. It (the yolk) should be provided occasionally and in small portions since it can easily foul the aquarium water. Another excellent option is specialized commercial foods to feed fry. They are not easy to find but it is well worth trying.

Some experts are in favor of providing live food to the fry, since it´s an excellent source of protein; there’s no doubt about it. They suggest among the options baby sea shrimp and ground worms very well ground, so that they look like porridge. They also recommend Tubifex and bloodworm, which are also ground in the form of porridge.

On the other hand, there are those who oppose the use of live food, stating that there is a risk of introducing some fungus or infection into the aquarium, which can be fatal because of the low defenses of the fry. What they do coincide is that the fry fed with live food will grow healthier and stronger.

Fry must be fed 3 to 6 times a day during the first weeks of life at regular intervals: morning, afternoon and evening. A few minutes after each meal, it will be necessary to remove the excess food, to prevent the water from getting dirty and may later affect the fry health.  Moreover since they are very delicate, fry require water and temperature stable and optimal conditions.

Manual Spawning

It is a very risky procedure, which can injure and even kill fish, so it must be carried out only by experts (professional breeders and people with many years of experience).

One of the advantages of this method is that the number of fertilized eggs is greater, the loss of eggs is lower (because they will not be devoured by the parents) and finally, it allows us to choose the father and the mother without the intervention of others fish.

It is important to mention that not all sexually mature fish are suitable for this method. The fact that we have a mature fish doesn´t mean that it has eggs or sperm inside it. It´s necessary to carry out a whole process in order to induce them to reproduction. In the previous points, one of the most effective and effective processes in the world was described.

Returning to manual spawning, a small container about one liter capacity should be used. First the male is introduced, holding it with the thumb and index fingers on both sides of the urogenital orifice, which must be under the water. Then its sides must be gently squeezed. The sperm should be expelled easily. Move the container in circles, in such a way that the sperm spreads in the water.

Once this is done, the male should be placed back in his aquarium and the female should be held immediately repeating the same process. It must be done within a minute of when the sperm was expelled, otherwise the eggs will not be fertilized.Once the eggs are expelled and fertilized with the sperm present in the water, it will be necessary to extract the eggs and place them in the incubator aquarium.

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Common Diseases of Veiltail fish

Despite being fish that adapt very well to any aquarium condition, the veiltail fish are prone to certain diseases the swollen swimming bladder being one of the most common. It always happens when their diet isn´t enough varied or balanced, abusing of proteins and especially the dry food. It can also occur because of a poor aquarium maintenance which furthers the arising of bacteria.

The best option to deal with this problem is to place them in a separate aquarium and supply them with medicines. You must also raise the aquarium temperature so that the bacteria die.

veiltail fish: swollen swimming bladder

Fungus in the Caudal Fin

Another common problem of the veiltail fish in aquariums is the fungi.  A caudal fin that loses its color and becomes white, is the main indication of the presence of fungi. This happens mainly when the water in the tank is not enough oxygenated becoming an ideal place for bacteria or fungi to form. When this happens, you should improve the filtration and oxygenation of the aquarium and isolate the affected specimens.

Veiltail Fish in Aquariums

Veiltail fish are very sociable especially with other members of their species. For this reason it´s  convenient to have 4 or 5 specimens in a tank of at least 200 liters so they can relate.

They also interact very well with other Goldfish, such as the Shubunkin. The aquarium must be kept clean, constantly changing the water to avoid the appearance of fungi and bacteria. Therefore the water must be replaced regularly. Moreover, its ph. should range between 7 and 7.5 and the water temperature can be between 14 and 24 º C.


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