The Green Swordtail (Xiphophorus helleri) is a member of the family Poeciliidae which are the livebearers. These fish can get up to six inches long but seeing this in the aquarium is rare. The males caudal fin has a long streamer off the bottom edge, hence the name “swordtail”. These fish have been bred to exhibit many different color forms but the wild type specimens are a iridescent green with a red strip running from the head to the caudal fin. The “sword” is generally black and yellow. The fishes name “Xiphophorus” means sword bearer in Greek and “hellerii” is in reference to the Austrian botanist Karl Heller who provided the type and description of the fish while exploring Mexico in the mid 1800s.
Swordtails are native to Central America, predominately Mexico and Honduras, but escaped populations have established themselves in Africa, Hawaii, and parts of Australia. They can tolerate euryhaline conditions (fluctuating between salt and fresh) and this not only makes them hardy for aquariums, but also capable of surviving in a wide variety of habitats outside of aquaria. Their preferred habitat is streams with dense vegetation.
Swordtails can get quite large so a minimum tank size for a single specimen would be a twenty gallon (long) aquarium. These are social fish, and their livebearing life history is fascinating, so maintaining a small group in a larger aquarium (at least 40 gallons) would be quite enjoyable. Coming from streams, they appreciate flow in the aquarium and you will enjoy watching them play and exercise in it. Dense live plants will make swordtails feel right at home and create a beautiful slice of river right in your own home!
Swordtails feed on small invertebrates, and algae they pick off of rocks and plants in the wild. They are not picky, and since your specimens will almost certainly be aquacultured (it is harder to find wild fish than any number of captive bred ‘morphs’ commonly available these days) and as such, the fish will usually take appropriately sized flakes and pellets from day one. Supplement their diet with quality live and frozen foods and offer some algae or plant matter as well.
Swordtails are sexually dimorphic, meaning males and females look different. Females are larger, and males have the “sword” on their tail. Mature swordtails will spawn readily even for the most novice aquarium keepers, so get yourself an appropriately sized aquarium, offer them a good variety of quality food and before you know it you will have a tank full of multiple generations of swordtails.
Swordtails these days come in colors from “mickey mouse” to “koi” so finding something to suit almost any aquarium or taste is easy. You can rest assured that these fish are farmed sustainably, and are suitable for any aquarist willing to give them the space and care they need and will reward you with many offspring. Contact your LFS and ask for some high quality aquacultured swordtails today from Aquatropic!