Alfaro cultratus

Common Name- The Knife Livebearer     Water Conditions- Not Critical. Temp 74-82, Some water movement, plants     Behavior- A Very peaceful community fish.     Breeding- Separate gravid females into separate tank. May eat fry. 10-30 Young after approx.30 days.     Size- Females- 3.5 inches, Males- 3.0 inches     This fish occupies the upper level of the aquarium, adapted to feeding on insects from the surface just above them.     These are exceptionally hardy, and seem to adapt to most conditions. From streams and moving water, they require     some water movement and aeration. They are perfectly peaceful, and do not bother other tankmates, though they can     be picked upon. This is a beautiful yellow fish, very sleek and active with soft, subtle markings. On occasion this     line has produced leucistic individuals that are more a curiosity than a viably attractive mutation. There have been     about 20, but they have all been male and unwilling to breed. Their eyes were not blue, but silver with black irises     on an ivory or light amber colored body.     Keeping them in a tank that provides room to swim. 2-3 young pairs can be kept and will do well in a 10 gallon aquarium.    Older females can get fairly large, at up to about 3 inches, and you may find with a community of them that 20 gallons is     a minimum tank size for this species.     Our colony of breeders is kept in a 50 gallon bare bottom tank with a bottom layer of Java fern filling up the bottom     third of the aquarium (See Plants page). They are fed dry foods primarily, and they do very well when a culture of fruit     flies is kept for them. Otherwise they will take all other types of live foods, but generally do not feed off the bottom     of the aquarium. They will eat fry inconsistently- here they do, and females are given their own tank to drop their fry,     and the fry are raised separately. Others I know who are keeping the same line of fish have tanks full of the smallest     young seeming to swim comfortably with the parents. A combination of diet and water quality differences most likely     accounts for this. Your ability to raise a large group of them will depend on your removing the gravid females, and     then raising the fragile, small young on their own.         Here, these are a species that breeds seasonally. This fishroom is exposed to windows with light from outdoors, and the     room cools in the wintertime. As a result, these generally do not drop any fry from about September to about Mid-March.     Females become large and “stuffed” in appearance with a narrow black outlining of the gravid area when she is about to     drop fry. Sometimes a true black gravid spot is never really visible, her size being the only indication she is about to     drop. Young females can sometimes be kept in a net breeder, but generally they are too large and must be placed into a     5 or 10 gallon tank of her own with a moderate amount of plants. The young do not hide in the plants, however, and will     school in a tight group together just beneath the surface. They are elongated, transparent, and barely visible, with a     length of about 6mm. Broods average from 10 to 40 young. Provided with reasonably clean water, a tank with room to swim,     aeration and quality foods, these will do very well for you.         See other Care Guides Here