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This page will give a completely detailed profile of the selected fish, from A to Z. The profiled fish will be chosen randomly by Badman, and will come from the complete genre of tropical fish. New profiles are added on a regular basis. If you would like to submit a profile for the site please contact me. Don't forget to let us know you experiences with this fish by filling out the

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Green swordtails

Xiphophorus hellerii


    The Swordtail, one of the "classic" aquarium fish, has maintained its popularity throughout the years. Easy to care for and pleasant to the eye it's easy to see why.

Quick stats:

    Listed tank sizes are the minimum
    Size: 4 3/4 inches (12 cm)
    Tank: 20 inches
    Strata: Top, middle
    PH: 7 to 8
    Hardness: Medium hard to hard 10-30 dH
    Temperature: 72° to 82° f (21-28°C)


    Order: Percopsiformes
    Suborder: Cyprinodontoidei
    Family: Poecilidae
    Genera: Xiphophorus

Common name:

    Swordtail, Helleri

Image gallery:
    Additional species photographs


    Badmans' Forum



    Mexico and Guatemala

General Body Form:
    The males are elongated, with the adults having a long sword shaped Caudal fin extension formed from the eight lowermost fin rays. Females are more robust and lack the sword. In both sexes the Dorsal fin has a straight outer edge. There has been much cross breeding within the family to produce many different colors and fin shapes. Lyretail swords have an upper and lower sword and others have "high fin" Dorsal fins as well. I believe that the original wild form ids still the most beautiful and would highly recommend it.

    Because of the vast array of colors we see today in the hobby, I will outline the coloration of the Original wild Green Swordtail. The upper-side is Olive-green with the sides being Yellow-Green highlighted by Brown edges. A dark stripe runs from the nose through the eye down the length of the body and in males along the bottom of his sword, giving it an underlining effect. Also on the sides near this stripe is an area of iridescent light Green bordered in Red, which under certain light conditions is stunning. The coloration of the sword itself can be Green, Yellow, Orange, Red or any combination of these colors. The Dorsal fin is a Yellow-Green color with one or more rows of Red dots. All in all a very nice looking fish even without the cross breeding.


    An easily cared for fish that does well in all types of community aquaria. Give them a fairly large tank with live plants and open swimming areas, avoid too much driftwood as a rule the livebearers do not like acidic water. Although not a schooling fish they benefit by being kept with a large number of their own kind. Among the males there is a distinct hierarchy. Temperature range from seventy-two to eighty-two degrees. A very peaceful and hardy species.

    Rivers in Mexico and Guatemala.

    As the male matures the Anal fin develops into a structure for reproduction called the Gonopodium. The Gonopodium can be moved in almost any direction and stores the sperm in packs called spermatophores. Once the sperm is inserted into the female it fertilizers her eggs and the rest is stored in the Oviduct walls for later use. The eggs are very rich in yolk and the young develop by consuming their yolk stores. In light colored females pregnancy can be recognized by the growing dark body marking in front of the Anal fin.

    Young Livebearers are fairly large at birth and their development is very advanced. They can swim right away, which is needed to avoid their enemies including their parents who give no natal care whatsoever. The fry grow very rapidly and will eagerly accept fine flake food. An interesting fact on Swordtails is their ability to appear to change sexes. All young swordtails are female and if a potential male starts to develop early, he will continue to become a slender small male. If a potential male goes through a female stage complete with the typical female form and gravid spot, he will develop into a large thickset "late" male.


Your comments:


Please remember that the following comments are personal experiences and may or may not apply to your setup. Use them as guide to help better understand your fish, like us all individuals will behave differently under different circumstances.


From: Ryan
Part of this information is incorrect. Not all swordtails are born female. They just look like a miniature female. If you thought you had a female and it turned into a male, it is because males can hide their sexuality until they are quite large and then they will become the dominant male as they are the largest. It is a common trait that swordtails have. They do this so they are not hassled by other males although other males will try to mate with them and even continue to try and mate with them once they have developed a sword and a gonopodium.
From: HelterSkelter
You state that swordtails can change sex and are all female at first. This is incorrect. Genetically they are either male or female, this can not be changed! Late developing is a strategy ployed in some males to allow them self's to get much larger and stronger with less hassle from other males. These late developers however are then the best males your will ever see. I've commonly seen fish of a year old suddenly turn into males. However if you had studied this fish well you would of noticed it was never pregnant and had never given birth before. As for females that do change sex (yes it dose happen) this is due to hormone imbalances in old age which makes the secondary (external) characteristic's develop, like for example the gonopodium and the sword.
From: Charlie C
I agree that swordtails are easy to keep and generally hardy. The mixing of male and female in my opinion is a mistake as I started off with 5 3 years ago and now have 42 at last count. I had thought that I had segregated the sexes but apparently not. Have been unable to find any outlet for the surplus fish so far, so running out of overflow tanks.
From: Joyce
Green swordtails added a lot of excitement to my first community tank. They male was extremely active and a personable fish. The red swordtails I found more docile and not quite as entertaining.

From: Wil
Green swordtails added a lot of excitement to my first community tank. They male was extremely active and a personable fish. The red swordtails I found more docile and not quite as entertaining.

From: Felix
I have two black female swordtail fish and a green male one. I was surprised that one of the black female is really aggressive. She bit off half of my other female's tail. She also pick fights with my Betta and Gourami, now she is in solitary confinement.

From: Stephanie
I found the swordtail to be a great beginner fish. They are not hard to keep at all. I suggest that if this is your first time getting them you should by 2 females and 1 male, they seem to do very well in trios. My personal favorite is the green swordtail. They have spunk but are very docile with the other fish. I am now breeding swords and get about 450 living fry to sell each year with only 3 males and 6 females and they don't need encouragement to breed at all. I highly suggest these fish as pets and for breeding.

From: Ben
I have a swordtail who gave birth about a month ago. What was a little weird was that the babies appeared dead for a little over a day. I was going to get rid of the bodies the next day but when I looked in the breeder net there was app 15 swimming babies! What a shock. I had never heard of this "slow to swim" behavior. I have three females to one male and they are great fish.







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