Plastic tank dividers overlaid with mesh sheeting will allow fry to
escape predation in colony tanks of more carnivorous livebearers,
such as Belonesox belizanus.
mix will depend on your species. Newborn Poecilia fry usually
head for the surface, while Xiphophorus and stream-dwelling
livebearers stay near the bottom. Clusters of small stones
around the tank are helpful here as well. Java fern and/or one
of the mosses (e.g., willow moss, Java moss, etc.) make good
grazing and hiding places for fry. A few sprigs of moss placed
throughout the tank and covered with a light coating of gravel
can create a nice carpet after a while. More fry survive under
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Plant or rock clusters in the back corners and sides of the
aquarium make for handy nurseries for females and fry to
congregate. Consider the use of small perforated pots sold for ponds
or even small clay pots if you plan on “harvesting” or thinning out
your colony. Netting out livebearers from a permanently planted
aquarium is usually quite disruptive and always vexing!
This leaves the center of the colony tank as an open area for
courtship, mating, sparring, and other social behavior. It is not
uncommon for your first drop of fry to be eaten by the larger fish
in the tank. But with plenty of cover, combined with regular good
feedings (at least twice a day), some of the fry will survive. The
other fish in the tank will eventually grow accustomed to sharing
their space with young’uns, and the colony will go into production.
Sometimes it’s a good idea to raise the first drop of fry separately
for them to gain some size, ensuring a good brood of little fish for
the adults to get used to.
Another protection method employed by some livebearer
breeders is to utilize the plastic tank dividers commonly sold in
pet shops. But instead of using the pin-holed plastic sheet that
comes with the divider, the hobbyist purchases an inexpensive
hard plastic mesh sheet from a knitting store, cut to size. The
larger holes in these sheets enable fry to escape from hungry
adults. This may be especially helpful for carnivorous livebearers
from the poeciliid tribe Gambusini (Brachyrhaphis, Gambusia, and
The Breeder Setup
The creation of a new fancy strain of livebearer, one that no
one else has developed, is the dream of many a hobbyist. Some
livebearians enjoy the thrill of competition by breeding and raising
champion show fish. Both pursuits require a more specialized
livebearer aquarium system.
There are more breeder setups and techniques in livebearer
circles than I have space to mention here, but a few basic
designs can get you started. You can actually use just a single
tank, and constantly remove the less-desirable fish. A multi-tank system, while more difficult to maintain, is more efficient,
as it provides more control over matings. At minimum, this
• A tank for your mature breeders, preferably with the sexes separated.
Keep temperatures on the low end of the spectrum to maintain
longevity, and feed a lower-protein diet (try goldfish diets).
• A tank for breeding, birthing, and raising fry. Maintain higher
temperatures to accelerate birth and growth.
• A female grow-out tank.
• A male grow-out tank.
Optimally, feed the fry and juveniles multiple times per day with
a higher-protein diet, including micro dry food, freeze-dried or live
Daphnia, and live newly hatched brine shrimp. The latter is the
staple food of show folk.
Note I did not recommend the use of breeding traps. These
contraptions are usually too small and stressful for females. If you
are in a pinch for space, the “net breeders” offer the best water
circulation and temporary space for an expectant mother, or to
protect a batch of fry. Alternatively, a one-gallon or larger fish
bowl with lots of live plants like Anacharis makes a good birthing
There are more ways to enjoy your livebearers, and I will be
highlighting them this year—so please stay tuned! D