Jenynsia lineata 

    Common Name- The "One-sided" Livebearer
    Water Conditions- Clean conditions, Aeration, Some water movement, plants, 70-76 degrees.
    Behavior- A social, peaceful fish.
    Breeding- 5-10 large young approximately every 6 weeks. 
    Size- Females- 3.0 inches, Males- 2.0 inches

    This fish is rarely seen in the hobby, and though a few hobbyists keep them going for long periods, they 
    are not routinely kept. A strikingly attractive and active fish, they will do well when provided  with a few
    simple requirements.

    They are kept at the same temps as most of the fish here, around 72-78 degrees. And they do not require
    a large tank, though I would provide them with at least a 29 gallon as they are active, and the females will
    grow to about 2.5 inches, the males slightly larger than half that size. I keep 3 pair of breeders in a 10 gallon,
    moving any fry to grow out into other10 gallon tanks, and full grown fish are kept in 30 and 40 breeders.

    An interesting belief surrounded this fish for many years, which has only been recently disproven.
    Nicknamed "The One Sided Livebearer", it was thought the males could only swing their gonopodiums in
    one direction, either to the left or the right. At the same time, each female was born with a genital pore
    able to accept fertilization from only one direction- from the left or the right. So to have a successful
    fertilization, a "right-handed" male would need to mate with a "left-handed" female, and vice-versa.
    It is odd this species has been kept in the hobby for as long as it has without this having been finally
    settled- my experience has been that they breed just like any other. My initial group was 1 male and
    4 females. All 4 females became gravid, and repeatedly. If the one sided characteristic was true, and
    the distribution of left/right was even, the one-sidedness would be very unlikely!

    The secret to keeping these fish is to meet their metabolism needs- these are an active, busy fish.
    They seem to respond to each feeding as if they hadn't eaten in days- yet they may have just been
    fed a few hours before. They will survive on once a day feedings, and will even breed, but generally
    will do best if given more frequent feedings. I have found that when well fed they will not bother new
    fry the first few hours after birth, and the young can then be caught and raised separately. The fry are
    fairly large and active from birth. Most fry seem to survive if left with the adults, when they are well fed.

    Because of the heavier feeding, effective filtration that provides some water movement and aeration
    should be provided, along with consistent water changes. Though big eaters, they are not a "dirty"
    fish, in that they put out a lot of waste. 

    I have kept this fish a number of times over many years, and have always kept them by themselves-
    not because they weren't good community fish, but because they are highly valued, and I never
    wanted to risk having them injured by tankmates. Customers who have put them in with other fish
    tell me they are excellent tankmates, and a great addition to a special tank!

    See other Care Guides Here