Microalgal culture is a key procedure in fish hatcheries, but it is far from optimized and faces several problems remaining to be solved. Nannochloropsis oculata is an important live feed alga used to rear larvae of marine finfish commonly in the aquaculture. The N. oculata was cultured in an experimental tubular photobioreactor with 148.4 m(2) total effective surface area and with artificial light. Scale-up experiment was completed in a hatchery. The cell density of N. oculata was held around 283 x 10(6) cells mL(-1) after the 10th day. As a result of this study, biomass concentration spanned throughout the entire growth period and during the culture period of 70 days, totally dried by spray-dryer, corresponded to 21.357 kg dry weight biomass. This tubular photobioreactor was designed to grow algae throughout the year and especially in the main spawning season of different fish species. The results of the present study indicate that indoor tubular photobioreactor systems can be used for growing microalgae and provide many advantages comparing to open systems.