Abstract
Sailfin molly, Poecilia latipinna is one of the alien ornamental fishes in Indonesia. This fish has been found in the aquaculture area in Maros Regency, south Sulawesi as a pest. The research aimed to identify species and observe aspects of reproductive biology of sailfin molly. The study was conducted in the Bosowa Isuma aquaculture area, in Maros Regency from November 2017 to April 2018. Fish was captured using a gillnet. The catches were separated for fish identifying and reproductive biology purposes. For the observation of reproductive biology, the samples were separated by sex according to external morphology. Measurement of total length and weight using calliper (mm) and analytical scales (g), respectively. The gonads preserved in the 4% formalin solution, used for determination of gonad developmental stages and fecundity. Identification results showed that the molly fish found in the ponds was Poecilia latipinna (Lesueur 1821). The length distribution of male and female fish was 26-76 and 31-66 mm with a mean of 51 and 46 mm, respectively. Overall, sex ratio and mature gonads between male and female fish were 1: 2 and 1:10; the growth patterns of male and female were negative allometrics and isometric, respectively. This fish is spawn throughout the year with the peak of spawning in January. The number of larvae to be born (larval fecundity) ranges from 12-111 individuals with an average of ± 32 larva/female.