A simple method of feeding coregonid larvae on frozen zooplankton

7 days old larvae of Coregonus lavaretus L. (local name: ‘Blaufelchen’) were fed on zooplankton that had been frozen at—18°C for 1 year. 4 times per day the pieces of frozen plankton were added into the preaeration tank thus providing that freshly thawed zooplankters were offered to the fish. Within 10 weeks the fish reached a total length of 30.5 ± 5.5 ram and an average dry weight of 22 mg. Within this period the survival was 45 % of the initial number. After a period of 7 weeks feeding on long-term frozen pankton 400 fish were switched to living zooplankton and after 9 weeks 400 fish were switched to short-term frozen plankton. The growth of those fish that were fed on living plankton was significantly faster than it was when frozen zooplankton was given. A switch of coregonids which were prefed on frozen zooplankton to dry diet proved to be successful as soon as the fish had reached a body length of 40 mm.