A system of twelve 25-m<sup>3</sup> concrete nursery tanks was used to investigate the parameters affecting the intensive nursery rearing of postlarval (PL) Penaeus monodon. The effects of habitats, substrates, dietary formulation and feeding rate on PL15 shrimp performance and system water quality were studied in 2 trials in Thailand.
Results indicated that with water exchange at 20%/d, the maximum stocking density of between 500 and 1000 PL/m<sup>2</sup> achievable in the absence of aeration could be increased to at least 2000/m<sup>2</sup> with aeration. Increased stocking density led to concomitant increases in shrimp production to a maximum of 11.5 g/m<sup>2</sup>/d<sup>1</sup>, but decreases in individual growth rate and survival. Substrate, consisting of a 10-cm layer of riverine sand provided no advantage, but habitats comprising vertical mesh panels were beneficial to survival and production at high stocking density. Analysis of the optimum feeding rates of a pelleted diet revealed that PL 15 to 50 would consume a maximum of between 30 and 60% (depending on postlarval age) of their wet body weight per day at 4 feeds/day. Increasing the feeding rate up to this level however, resulted in problems with system water quality. A change in the reference diet to one containing higher levels of lipid, protein and dietary energy was inversely correlated to shrimp production.