If you are looking for bright, active, and unpretentious inhabitants for your aquarium, be sure to take a look at swordtails. These fish have long won the love of aquarists around the world, and for good reason. Their main “feature” is the famous sword-like growth on the tail of the males, which gave this interesting group of fish its name.
Swordtails are real live wires. They are constantly on the move, playing in the water currents and adding dynamism to the aquarium. At the same time, they are very peaceful and get along well with other small neighbors. They also impress with their variety of colors: from classic red and lemon to spotted and even black.
In this article, we will look at the different types of these fish, what they need for a long and healthy life, and how to create the ideal conditions for them in your home aquarium. You will see that keeping swordtails is a pleasure that even a novice aquarist can handle.
Habitat and lifestyle
The original habitat is located in North America (Mexico) and Central America (Nicaragua, Honduras, Guatemala, Belize, El Salvador, Panama). The species inhabits everywhere from mountain rivers with rapid currents to stagnant water bodies (swamps, lakes, ponds) . The fish prefers to stay close to areas with rich aquatic vegetation, where it searches for food in the form of insects, phytoplankton, and bioplankton. It spends most of its time in the upper layers of the water, picking up food on the surface.
In the second half of the 20th century, this species became popular around the world as an aquarium fish, so it spread to other continents. Now swordtails can be found in the waters of India, Africa, the USA, and Europe. The fish adapts well to new conditions, sometimes displacing native species.
Swordtails live in schools. There are usually several females for each male. Males fight each other for the right to possess a harem of females. This rivalry often leads to death. Females do not fight at all, but they can turn into males by modifying their sexual organs.
— Dmitry Sudakov, Moscow, has been keeping aquariums for 12 years
Appearance
The fish has an elongated, streamlined body, compressed on the sides. The body length (without the tail) reaches 10-12 cm. The snout is pointed, which is typical for fish living in strong currents.
A distinctive feature is the long, elongated lower part of the tail in the form of a sword, which is where the species gets its name. The length of the “sword” can reach 80% of the body length. Moreover, only males have a “sword”; females do not.
The mouth is turned upward to collect food from the surface of the water. At the same time, the eyes are located approximately in the center of the head, which is unusual for surface fish species and indicates the versatility of the swordfish, which can change its horizon and search for food in the middle or even bottom layers if necessary.
In their natural habitat, swordtails are silver, yellow-green, or olive in color with shades of orange, brown, and red. Artificially bred varieties can be practically any color.
Sexual dimorphism is pronounced. Males are smaller than females and have a distinctive “sword” on their tail. Females are usually lighter and paler in color than males. The anal fin of females is wider and fan-shaped.
Males have a slender, elongated body, while females have a rounded, wider body. During the spawning season, males may become more colorful.
Care
Swordtails are undemanding in terms of care, but you should still try to make them as comfortable as possible, which will have a positive effect on their health and lifespan.
Aquarium
One male and several females are usually kept in one aquarium. This requires a tank with a volume of at least 50 liters. For a larger number of individuals (primarily males), an even larger aquarium is necessary. Males often fight among themselves, so they need more free space. The aquarium must be covered with a lid so that the fish cannot jump out.
Water requirements
A filter and aerator are essential, as swordtails like clean, oxygen-rich water. It is advisable to create a small current.
The optimal water temperature is 20-26°C. Fish tolerate temperatures below 18°C well, but this causes them stress, so it is not recommended to experiment. Moreover, different species or populations may react differently to changes in conditions. The dH level is 2-25, pH is 7-8.
An important feature of keeping swordtails is that they do not react well to fresh water. It is unclear why this is, but water should be added no more than once every two weeks. For this reason, swordtail neighbors should be carefully selected. It is also important to add salt to the aquarium at a rate of 1 g per 1 liter of water. At the same time, the resistance of other fish species to salt water should be taken into account. Salt is needed to protect fish from parasites, fungi, and possible diseases.
Substrate
Swordtails do not pay attention to the substrate, so it is chosen as part of the decor. You can use small or medium pebbles, as well as sand. The color of the substrate should contrast with the color of the swordtails. It is also recommended to plant underwater plants in the substrate, which the fish may like.
Vegetation and decor
In their natural habitat, swordtails live among plants, so they are an integral part of their lives. Without plants, the fish will be stressed. At the same time, it is important to take into account the high activity of the fish, which requires a large amount of free space. It is best to plant plants in the corners and along the walls of the aquarium. It is recommended to place several driftwood pieces on the bottom so that the fish have a place to hide and rest.
Lighting
This species prefers well-lit water bodies, but the light should be diffused and not too bright. It is also important to consider the number of plants and the size of the aquarium.
Feeding
This is an omnivorous fish that can be fed almost anything:
Young individuals need to be given more protein-rich food. Adult swordtails are fed a 50/50 protein and plant-based diet. They are prone to overeating, so once every 7-10 days, a fasting day should be arranged.
Fish are fed 2-3 times a day in small portions. They prefer to gather food in the upper layers of water, less often in the middle layers. They do not pick up food from the bottom, so it must be removed manually to prevent the water from souring.
Reproduction
This species does not lay eggs, but carries the fetus in a special organ. Fully formed fry appear, which can live independently from the first minutes. This is an ovoviviparous method of reproduction. Females can be distinguished from males by their sword-like appendage and anal fin (gonopodium).
The male inserts the gonopodium, which is a tube with a groove for seminal fluid, into the female's abdominal cavity through the anal opening. No special conditions are required for reproduction. Spawning occurs naturally several times a year.
Pregnancy lasts 35-40 days. Several factors influence the gestation period: water temperature, nutrition, light level, age, etc. Pregnant females increase in size and their abdomen becomes rounded. A birth spot appears in the anal opening area. A female can give birth to 20 to 100 fry at a time.
To save the offspring, it must be transferred to another aquarium, as adults will eat the fry. Even the female may begin to feed on her young, as she has no maternal instinct. In the natural environment, the fry are carried away by the current, so the female does not come into contact with them.
Newborns are 5-7 mm long. They can feed on cyclops, tubifex, infusoria, and artemia nauplii. Dry food for fry is also suitable for them.
They grow very quickly. By the third month, they are almost as big as their parents and can be fed like adults. They reach sexual maturity at 5-6 months of age.
Varieties
There are a large number of subspecies of swordtails, which can vary significantly in appearance.
Natural species
First, let's look at the species found in the wild:
- Montezuma swordtail (Xiphophorus montezumae)
Endemic to northeastern Mexico (Nuevo León and Chihuahua states). Named after the infamous last emperor of the Aztecs. Body length does not exceed 5 cm.
Their color is silvery-blue with a mixture of yellow and green. The sword-like appendage can exceed the body length by 1.5-2 times. Due to its unattractive appearance, it is not popular, although this species is quite easy to keep.
- Dwarf swordtail (Xiphophorus pygmaeus)
Found in fast-flowing rivers and streams in Mexico and Central America.
Its body length does not exceed 4 cm. Females are pale beige in color, while males are silvery blue. Black or brown stripes run along the sides.
- Yellow swordtail (Xiphophorus clemenciae)
Lives in Central America in small bodies of water with moderate currents.
The body and fins are yellow in color. The lower part of the body is silvery blue. The body length does not exceed 5 cm. The sword-like protrusion has black edging.
- Chiapas swordtail (Xiphophorus alvarezi)
Found only in the Mexican state of Chiapas. Prefers mountain rivers and streams with fast currents.
The body length reaches 9 cm (with a sword-like protuberance up to 15-17 cm). The body is orange with elements of green and blue. Females are noticeably paler than males. The sword-like protuberance of males is bright green with black edging.
- Delicate swordtail or Cortez swordtail (Xiphophorus cortezi)
It inhabits Mexico and Central America. It prefers freshwater ponds with clean water. It has an unusual coloration, combining yellow, white, green, and black colors in the form of patterns. Its fins are covered with black speckles and yellow spots.
Males have brighter and more colorful plumage than females. The sword-like protuberance is relatively small, up to 30% of the body length. Females grow to 7-8 cm, males to 5-6 cm.
- Birchmann's swordtail (Xiphophorus birchmanni)
Found only in the Panuko River in Mexico. Has a bright, memorable appearance.
The body color can be blue, pink, or purple with transverse black stripes. The fins are bright yellow in males and pale pink in females. They are covered with a large number of small black spots. The sword-like protuberance is barely noticeable.
- La Malincha swordtail (Xiphophorus malinche)
Also inhabits only the Panuco River. Named after the Indian slave La Malinche, who was the secretary of the conquistador Hernan Cortez. Body length reaches 5-6 cm.
Its appearance is relatively dull. Males have a bright yellow back with longitudinal black stripes, while females are almost completely silver or blue with yellow fins. The sword-like appendage is short (1-2 cm).
- Mayan swordtail (Xiphophorus mayae)
It inhabits Central America in Guatemala and Honduras. It grows to 4-5 cm.
The body is greenish-yellow with three distinct red longitudinal stripes. The sword-like appendage is approximately equal to the length of the body and has black edging.
- Short Swordtail (Xiphophorus continens)
It lives only in the Panucan River in Mexico. Its body length does not exceed 4 cm.
The Latin name comes from the Greek conto, which means “short.” The fish has a barely discernible sword, which is only a few millimeters long.
- Panucan swordtail (Xiphophorus nigrensis)
It is found only in one location in the Panuko River. Its closest relative is the dwarf swordtail.
It differs from the Panuca species in its larger size (up to 6-7 cm) and pronounced black stripes on the sides of its body.
- Nezahualcoyotl swordtail or mountain swordtail (Xiphophorus nezahualcoyotl)
Named after the Aztec emperor, poet, and philosopher Nezahualcoyotl, who lived in the 15th century. Another endemic species found only in the Panuko River. Reaches a length of 7-8 cm.
The body color can be azure, blue, pink, greenish-yellow, and white with a large number of black spots of various sizes. Sometimes the spots form a blurred longitudinal line. The sword-like protrusion reaches a length of 80-100% of the body length.
Artificial varieties of swordtail
Several dozen varieties of swordtails have been bred.
Let's look at the most popular morphs:
- Berlin
It is distinguished by its bright orange color with black dots all over its body. The sword-like protuberance is black.
- Black
It has a black color with a blue or azure tint. The sword-like protuberance is black with yellow edging. The fins are yellow or orange.
- Tiger
The body is red with black spots and stripes, like a tiger.
- Bulgarian white
The front part of the body and head are bright orange, the rest of the body is white.
- Koi
The head and front part of the body are bright orange, the middle part is white with black spots, the rear part and tail are black with orange spots.
- Koi-kohaku
The head and rear part of the body are orange, the middle part and fins are white.
- Blood red
Completely colored blood red. The dorsal fin is high and sail-shaped, also red.
- Neon
The upper part of the body is yellow-orange, the abdomen is pale yellow. The sword-like protuberance is orange with black edging.
- Red joker (black-tailed)
The body is reddish-orange, the tail is completely black.
- Pineapple
The color of the fish resembles the color of pineapple pulp. The front part of the body is light yellow, the back part (including the tail) is bright orange. There are red stripes of dots on the sides. Males are noticeably narrower and more elongated than females and have a larger dorsal fin.
- Veiltail
The upper part of the body is red, the lower part is completely black. The tail and fins are red or orange. A distinctive feature is the wide tail and dorsal fin, which resemble a veil.
- Tuxedo
The body is almost entirely red with a wide black stripe that starts in the middle of the body and ends near the tail. The fins are yellow-orange.
- Red velvet
The upper part of the body, fins, and tail are light orange. The lower part of the body is red. The sword-like protuberance is orange with a black stripe at the bottom.
- Panda
It has a pearlescent body color with a hint of purple near the head. The tail, sword, and fins are black.
- Golden
Completely golden in color. It has several sword-like protuberances on its tail.
- White
The body color is milky white. The eyes and the area near the gills are pale red. The upper part of the tail is pale yellow.
- Santa Claus
Most of the body is silvery white. The head and the area of the back near it are red. A small area near the tail is red or orange.
- Lyrocha
The color of the body, tail, and fins is bright orange or amber. A distinctive feature is the tail with two long appendages, like a lyrebird.
- Cotton
The head and front part of the body are bright orange. The rest of the body is covered with black, white, orange, yellow, and blue spots. The fins are light blue.
- Rainbow
The upper part of the body is bright orange, the abdomen is silvery. Dark orange stripes run along the body, which shimmer in the light.
- Mickey Mouse
It can be yellow, red, or orange in color. A distinctive feature is the pattern near the tail, which resembles Mickey Mouse in outline.
- Flag
Dark orange body with a black tail and a sword-like protrusion. It is distinguished by a high dorsal fin, similar to a raised flag.
- Sailfin
The body and fins are bright orange. A distinctive feature is the long, wide fins, which resemble a sail.
- Swordfish of Hell
The front part of the body, head, and part of the abdomen are silvery with a blue sheen. From the pectoral fins to the tail, the body is bright orange. The tail, sword, and fins are coal black. The dorsal fin is tall and wide, like a sail.
- Green
The body is silvery-green with a yellowish and bluish tint. There are longitudinal red or brown stripes on the sides of the body.
- Cuban
The lower part of the body is black, all other parts, including the tail and fins, are bright orange.
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- Lemon
Completely lemon-colored. Only the sword and part of the tail have black edging.
Compatibility
For the most part, swordtails behave peacefully towards their relatives and other aquarium inhabitants. Problems arise if there is not enough space in the aquarium or if there are too few females per male. Then the males become aggressive and attack other fish.
They can be kept with the following species:
Not recommended to keep with:
More care tips:
Swordtails are bright, undemanding fish that are ideal for both beginners and experienced aquarists. They are distinguished by their calm temperament, active behavior, and characteristic sword-like growth on their tail, hence their name. These fish get along easily with other species, but it is important to maintain a balance between males to avoid conflicts. They are easy to keep: you need an aquarium of at least 50 liters, clean water, plants, and regular feeding. With proper care, swordtails live long, delight the eye with their bright colors, and can even reproduce right in your home aquarium.
Video review of swordtails and their care requirements
Swordtails are an excellent choice for both beginners and experienced aquarists. Their bright appearance, active behavior, and amazing ability to reproduce right in the community aquarium make watching them a truly fascinating activity.
Remember that behind their apparent simplicity lie certain needs. They need a fairly spacious aquarium with clean water, a varied diet, and the right choice of tank mates. If you provide them with these basic conditions, swordtails will reward you with good health and a long life.
Don't be afraid to experiment with different species, from classic green to striking red and black koi. Each of them will bring its own flavor and bright color to your home underwater world. Good luck with your pets!
