Swordtails are everywhere in the aquarium trade. You can find them at virtually any big box pet store or specialty aquatics shop. They are popular among new and experienced aquarists alike for their hardiness, ease of care, and communal nature. Because of their popularity, there are many varieties of them available.
If you’re looking to start a new tank or are wondering whether you can add swordtails to your existing community tank, you will find helpful information in this article. We’ll touch on a few of the different varieties of swordtails out there, how to care for them, and some interesting facts about them. We’ll also talk about how you can encourage them to reproduce.
3 Types of Swordtail
The swordtail gets its name from the sword-like caudal fin possessed by males of the species. Females of the species do not have this elongation and instead have less pronounced tails, more closely resembling their relative the platy.
In nature, the swordtail fish (Xiphophorus helleri) is primarily a light olive green color. However, due to extensive breeding in the aquarium trade, there are many varieties of the fish. There are over 30 different color variations available today that can present alongside multiple body and fin shapes.
The three most commonly encountered types of swordtail are the lyretail, hi-fin, and longfin varieties. The first of these, the lyretail, has elongated rays on the top and bottom of the caudal fin. These elongated portions are split from the central portion of the caudal fin, giving the tail an elegant, feathery appearance. The swords of male lyretails may turn slightly upward at the end as well.
The second, the hi-fin variety, features a prominent and very flowy dorsal fin. At rest, this fin may fold down gently over itself and the fish. Some hi-fin swordtails, sometimes called sailfin swordtails, have more rigid, branching rays that produce shapelier dorsal fins.
The third commonly available variety is the longfin swordtail. As its name suggests, this variety features very flowy and elongated dorsal, pectoral, and caudal fins. Depending on the genetic lineage, these fins can become exceptionally long.
How to Care for Swordtails
Caring for swordtails is straightforward. They are great in groups and don’t like to be alone. Below, we’ll talk about how much room these fish need at a minimum, what to feed them, and their ideal water parameters.
Tank and Tank Size
Swordtails are active fish and like a lot of room to move around. It is usually a good idea to oversize and understock a tank to allow your fish the most freedom of movement.
A bare-minimum rule to adhere to is to set up a tank that is sized for 1 inch of adult fish length per 1 gallon of water and then round up. Since swordtails can reach about 6 inches in length, the minimum tank size for a single adult fish might be around 10 or 15 gallons. Since swordtails do best in groups of 4 to 6, you’ll want to add at least 5 or 6 gallons to your tank size for each fish you plan to add.
Male swordtails can become territorial, especially when crowded, so more space and obstacles are better. Having plants and decor that can break up lines of sight and allow fish to hide from each other is important in reducing stress.
Because swordtails hail from Mexico and Central America, they fare best in water that remains between 72 and 79 degrees Fahrenheit year-round. This makes them great community fish, as this temperature range is common for tropical fish.
In general, these fish are not overly picky about their water parameters. You’ll want to aim for a pH range between neutral (7) and alkaline (8), but some aquarists have luck housing swordtails in slightly acidic water as well.
Any tank that houses fish should be well-cycled and maintained at 0 ppm ammonia and nitrite. Perform regular water changes to keep nitrate levels low and maintain tank cleanliness.
Because they are omnivores, swordtails thrive on a varied diet. They will usually eat just about any commercially prepared flake or pelletized fish foods. However, your fish will appreciate the addition of live, frozen, and freeze-dried foods into their diet. Some options include thawed brine shrimp and daphnia, spirulina, seaweed, and bloodworms. Thawed mysis shrimp is a great and very nutritional staple option as well. The amounts of each that you should feed your fish will vary depending on the number of fish you have and how big they are.
How to Breed Swordtails
Swordtails are extremely prolific fish, producing as many as 150 fry at a time. They are also very unique in that they are livebearers. Unlike many other fish, they do not lay eggs during reproduction. Instead, they gestate for about a month and give birth to many tiny free-swimming fry.
If you have a mix of male and female fish and they are comfortable in their environment, they will almost certainly reproduce on their own without your intervention. In tanks that are too small or are very crowded, they are unlikely to do so.
If you would like to ensure that the newborn fry survives, it is best practice to separate a pregnant swordtail into her nursery tank when she is ready to give birth. It should be set up just like any other tank, with hiding spots, appropriate filtration, and heating. Ideally, there will be foliage or hardscaping to provide cover to the newborn fry, as the female will likely try to eat them soon after they are born. At this point, you can carefully remove the female from the nursery tank. Fry must then be fed size-appropriate food multiple times a day starting at birth.
If you aren’t interested in breeding your swordtails or don’t think you have the time and space to handle the whole process, you can simply opt to stock your tank with one sex or the other.
The photo featured at the top of this post is © topimages/Shutterstock.com
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