Putra, Ridwan MandaWindartiSimanjuntak, Esa F2016-04-042016-04-042016-04-04978-602-17943-2-6wahyu sari yenihttp://repository.unri.ac.id/xmlui/handle/123456789/8177Belontia hasselti is belonged to Belontiade family and commonly inhabit flood area and irrigation canals in palm tree plantation areas in Riau. This fish is commonly consumed by local people or reared as aquarium fish. However, information on reproductive biology of this fish is rare. To understand the reproductive biology of this fish, a research has been conducted on February-April 2012. There were 123 fishes (102 males and 21 females) captured (52 to146 mm TL and 2 to 68 grams BW). The sex ratio of male and female is 5:1. In each sampling time there were fishes with 1st, 2nd, 3rd and 4th maturity level. The Gonado Somatic Index (GSI) is around 0.01-10.46 %. Fecundity is around 142-10,041 eggs. Relationship between fecundity and TL is weak (R2=0.01), while the relationship between fecundity with BW is strong (R2=0.99). The egg diameter is 0.98-1.00 mm. Histological study shown that the maturity stages of eggs in the ovary is various. In the 1st maturity level, the ovary consists of non vitellogenic eggs (diameter 0.05-0.18 mm). In the 2nd maturity stage, the ovary consists of non vitellogenic and early vitellogenic (0.15-0.44 mm). In the 3rd maturity level, vitellogenic eggs occur (0.28-1.95 mm) and in the 4th maturity level, most of egg in the ovary are mature (0.3-0.5mm), but there are non vitellogenic and early vitellogenic eggs. This evidence indicates that B. hasselti may be a “partial spawner” and it may spawn their eggs throughout the year.enB.hasseltiBelontidaesex ratioGSImaturity levelfecundityUR-Proceedings