The culture diets were fed manually 8 times a day at 3 h interval.Temperature was kept constant at 27 °C using submerged heaters.Harvesting of the rotifers was performed at the beginning of day 4. Forthe traditional culture/enrichment experiment rotifers were enriched during 3 h in 450 l tanks at a starting density of 3000 individuals·ml−1 and a single enrichment dose of 0.17 g·mill−1