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Green Swordtail

Xiphophorus hellerii

Family: Poeciliidae
Genus: Xiphophorus
Species: X. hellerii
General Facts
Life Span: 3-4 years
Size: 6 Inch(es)
Temperament: Peaceful
Strata: Top, middle
Diet: Omnivorous
Water Chemistry
Temperature: 21 to 28 °C
PH: 7 to 8
Water Hardness: 10-30 dH
Binomial name
Xiphophorus hellerii
Common Name(s)
Mexico, Belize, Guatemala and Honduras


Swordtail is the second most famous fish in the aquarium hobby. They are very peaceful fishes which make them a very good addition for the community tank. Apart from being a very famous aquarium fish they are used in cancer research.

Body Formation And Colour

The colour of a wild type swordtail fish is olive green. The top of the body looks olive green in colour. In the male the sides are in glittering green colour. A maroon colour line runs horizontally from the eye to the beginning of the caudal fin for both males and females. The eyes will be in black colour. Males look more shiny than females. The sword like caudal fin of males have a think black contour. The dorsal fin has red dots which is more prominent in males. Males have gonopodium and females do not have. Males have a sword like formation at the bottom of its caudal fin.

Care And Maintenance

Swordtails are very good jumpers. Hence the tank should be properly covered. The dominant male always bully other males. If the other male is very small or weak then it sometimes torture them to death. Females do not bully males or other females and males do not bully females. This fish has been domesticated for a very long time and they tolerate wide range of temperatures, PH range and water hardness. They almost can survice on any decent water condition. However these fishes should not be taken for granted. They live longer and look brighter if they are cared well.

Diet And Feeding

Swordtail fishes are omnivorous. They can almost eat anything that is edible. They can eat live worms, brine shrimps, earth worms, algae, flake food, their own fry etc. They are good algae eaters and do not eat other plants in the aquarium. Hence they are good adition for any planted tank.


Rivers and fresh water drainages.


Males have gonopodium and a sword like caudal fin. Females do not have gonopodium nor a sword like caudal fin. They reach maturity when they are around 3 months old. Some males show gonopodium and sword like caudaul fin very late in their life span compared to other males. Most of the times it is mistaken for changing sex, by the hobbyists. Belly of female is more round compared to males.


Breeding this fish is similar to breeding any other live bearers. Leave a male and female in a tank with lot of room for them to swim around. The male will swim fast following the female, flaring at it and display its best colour to attract the female. Since most of the time the male will be chasing the female, It might be annoying for the female. Hence it is better to maintain the ratio of two females per male in a tank. It is said that swordtail females like other live bearers stores the sperm inside her for atleast six to nine months. So a female once mated with a male can give birth to young ones for atleast six to nine months with out a male. A female gives birth around every thirty days. Like any other liver bearer fry, swordtail fry are comparitively bigger than fry of egg laying fishes. On an average a female can give birth to 30 – 200 fry depending on the size, age and other factors. Swordtails do eat their babies. Hence if you want to save the fry keep lot of plants and other aquarium decorations in the tank so that the fry have lot of hiding places. It is better to remove the fry and care for them by keeping them in a seperate tank.

Fry Care

Since the swordtail fry are bigger they can take crushed flakes or baby brine shrimp/artemia. The fry grow faster if they are given large space. Otherwise their growth will be stunt.


There are lot of known variants in this fish by colour and fin formations. Apart from the sword type caudal fin and normal type fins in other parts of body, there are lyre tails, high fins and fishes with long pelvic and or gonopodium. When it comes to color there are numorous variations. The most common is the red colour. It is so common that lot of people think the wild colour of swordtail is red. There are other colours like black, pineapple, tangerine, white. The while is mostly an albino with red colour eye. Comparitively most recent addition to swordtail world is red and white Koi swordtail.


Fin Variants

Apart from normal caudal, anal and dorsal fins. There are Lyre tails, Hi fins and long anal fin variants.

Binomial Nomenclature: ,

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