Extended BAP Article—LIV Specialist
The Black Sailfin Goodeid
Girardinichthys viviparous
by Chase Klinesteker
SouthWestern Michigan Aquarium Society. From SWAM, March/April 2004 Issue
Aquarticles
The Girardinichthys viviparous, commonly known as the Black Sailfin Goodeid,
is rare and severely endangered. Mexico City is built on its limited habitat. It is a
small livebearing fish that is difficult to keep, but is also quite attractive. The
dominant males have their tail, dorsal, and anal fins at least edged in black, and
sometimes these fins are totally black. The dorsal and anal fins are proportionately
larger on these males than on most other goodeids, hence the name "sailfin".
Females get up to 6.5 cm in size, with the males somewhat smaller. Gestation is about 55
days and a female can have from 2 to 25 young. If well fed and in good quality water, they
will not eat their fry. Both sexes have a black gestational (gravid) spot.
Their native waters are slightly salty with temperatures ranging from 45 to 85 degrees
F. Mine seemed to do fine with no salt added. They do not seem to do well much above 70
degrees F. for me, and lower temperatures were the key for me in keeping them alive. I
kept them in a bare bottomed 20-gallon tank with floating hornwort and potted plants.
Some live food is important, but I would keep away from a lot of worms. Newly hatched
brine shrimp is greatly relished, as well as frozen brine shrimp and various flake foods.
I found that they likely need some vegetable matter in their diet and fed mine a good
proportion of spirulina flake food. These fish pick a lot on the bottom and will clean up
most food left there if given the time. Several snails added to the tank will insure that
excess food will not last long. They need to be fed often and well to get the growth and
reproduction.
The problem is that they are sensitive to the pollution created. This is why they are
considered difficult to keep and breed, but if one doesn't overcrowd, siphons up debris,
cleans the filter, and does frequent water changes, success can be attained. The care and
breeding of this species is difficult and regular water changes and filter cleanings are
necessities.
These fish are susceptible to fish tuberculosis and you may notice it when a one of
them float up and try to swim down. You can sometimes see a growth on the liver going into
the air bladder. They should be removed and destroyed right away as it is very contagious.
Clean water and a varied diet appears to prevent this.
I recommend to others that they keep and try to reproduce the Black Sailfin Goodeid.
Besides the satisfaction of succeeding with a difficult and attractive species,
reproducing and distributing these fish to others ensures the species will continue in the
future.
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