© 2019 Chase Klienstecker

Website Designed by 4ten Design & Photo

All Rights Reserved.

Black Sailfin Goodeid

Girardinichthys viviparus


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 dominate 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.  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. 



The care and breeding of this species is difficult and regular water changes and filter cleanings are necessities.  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 also.  I kept them in a bare bottomed 20 gallon tank with floating hornwort and potted plants.  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 but 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.  Gestation is about 55 days and a female can have from 2 to 25 young.  These fish are susceptible to fish tuberculosis (you can sometimes see a growth on the liver going into the air bladder) and they float up and try to swim down.  They should be removed and destroyed right away as it is very contagious.  Clean water and a varied diet seems 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.