SOME BIOLOGICAL STUDIES ON THE TWO SPOT GOURAMY : TRICHOGASTER TRICHOPTERUS (PALLAS)

Abstract

A general survey is made of the ecological role of Trichogaster trichopterus (Pallas). The species seems to favour swamps I rice-fields and ditches where the shallow stagnant water with a muddy substratum is conducive to the feeding and air-breathing i-equirements of the fish, Tricho15astei- trichoptcrus is basically a bot tom browser but it changes from micro carnivorous feeding in the fry to algal and dotritophagic feeding in the adult. The scales and otoliths do not have growth checks while tagging and marking the fish wore found unsuitable for growth studies, Hence the length frequency data from a selected habitat were used and the results compared to those obtained undur uquarium conditions, The growth pattern of Trichogaster trichopterus conforms to the generalised pattern of a sigmoid curve, It grows to muturi ty in four to five months depending on the environmental conditions and food supply. Tho length ,veight relationship provides a useful means for converting growth rate data from length to woic;ht and in assessing the length at first maturity of tho fish throur,h the fluctuating values of the relative condition factor Kn, with increasing longth, Direct gonardexamination shows that the, onset of maturity occurs nt about a standard length of 45 mm irrespective of sex, From this size onwards rapid mnturation of gonad ensues until tho fish attains full maturity around the 60 mm standard length, Field observations nnrl ovn-rliamc,tor frequency r,tudy indicate thut Trichop;aster trichortorus is a continual spnwnor without n.ny mnrked spawning season. The focunrlity of the fish is low but thirs is offsottm by frequent breodinr, and the display of pnrontal care,