Spermatogenesis of Siamese Fighting Fish, Betta splendens, Osphronemidae, Teleostei

Abstract

Taxonomically, Betta splendens, which is generally known as Siamese fighting fish belongs to the Osphronemidae. The common name ‘fighting fish’ came from their specific behaviors. When two males encounter each other in the same living place, typical pattern of aggressive behavior is occurred (Figler, 1972; Lobb & McCain, 1976). The labyrinth organ, which is situated on either side of the head in the gill cavity directly above the gills, allows Betta splendens to have ability to breathe atmospheric air (Bailey & Sandford, 1998). Generally, spermatogenesis of teleost varies depending on species and inhabited environments. The spermatogenesis of fish has been studied in some species, Liza aurata (Brusle, 1981), Salmo gairdnen (Billard, 1984), Acanthopagrus schlegeli (Gwo & Gwo, 1993), Boleophthalmus pectinirostris (Chung, 2008), Atlantic cod, Gadus morhua L. (Rebours & Ottesen, 2013) and Epinephelus bruneus (Kim et al., 2013). There are various studies about Betta splendens in relation to their aggressive behavioral responses (Thompson & Strum, 1965), intrasexual communications (Doutrelant et al., 2001), sex reversal (Pandian & Sheela, 1995), and development (Mabee & Trendler, 1996). Also, there is a study focusing on changes of testis followed by aging under light microscope (LM) (Woodhead, 1974). But there are few studies and limited information about spermatogenesis in ultrastructural approach of Betta splendens. Moreover, to increase understandings about hormonal effects regarding to their patterns of behaviors (Kirankumar & Pandian, 2002), it is necessary to investigate spermatogenesis of Betta splendens. Especially, in contrast to sperms of genus salmo and genus Oncorhynchus (Alfert, 1956) which spawn demersal eggs, settled under the water, sperms of Betta splendens spawn pelagic eggs which float on the water. The differences between each sperm spawning demersal and pelagic eggs, respectively, are expected regarding to spermatogenesis and Spermatogenesis of Siamese Fighting Fish, Betta splendens, Osphronemidae, Teleostei