In this study, three tails of TGGG hybrid grouper were dissected and sacrificed in observing the gonad availability. Only three tails of TGGG hybrid grouper were selected to be sacrificed because if by sacrificing the whole population of TGGG hybrid grouper to observe gonad availability, it would considered to be a big loss. These TGGG hybrid grouper is very important and valuable because the current fish that was used for this experiment was the first batch of TGGG hybrid grouper production [1]. Still, other method such as determination of sexual maturation through biopsy (which sacrificing the fish is not necessary) [29] could be done in the future for TGGG hybrid grouper.