The paper details the observations made on the natural spawning of honeycomb grouper (Epinephelus merra) achieved at the Regional Centre of Central Marine Fisheries Research Institute (CMFRI), Mandapam Camp. The construction details of indoor maturation and spawning system developed for the captive maturation and natural spawning of small sized groupers are given. Sub-adults of this species were collected, maintained, developed into brood stock and transferred to indoor maturation tank for observations on natural spawning. The natural spawning occurred between August and October 2004 and corresponded to the lunar phase of each month. Number of eggs, percentage fertilization and hatching, the water quality parameters, feeding protocol adopted for sub-adults and brood stock are detailed. Disease occurrence and their control, importance of PUFA enriched feed are also discussed
