5. Conclusion Our study is the first to investigate the effectiveness of a FOFD strategy at two different temperatures for rainbow trout after growth on the novel palm based oil – PFAD. The growth of 75% PFAD fish was impaired at 15 C, implying that high inclusion levels (>50%) of PFAD in diet for rainbow trout grown at this temperature is not beneficial. Feeding a 50% PFAD diet during the eleven week grow-out period followed by a finishing FO diet for four weeks was sufficient for a large restoration (85–98%) of EPA and DHA % values in rainbow trout fillet and whole carcass. The 4 week finishing period for fish previously fed 75% PFAD resulted in lower restoration (66–93%) of %EPA and %DHA rainbow trout fillet. We showed that the dilution model was suitable to predict %FA modification occurring in the fillet and whole carcass of rainbow trout after dietary change from different dietary levels of PFAD to FO and there was no evidence for FA turnover or preferential FA metabolism. Although a large restoration of %EPA and %DHA was achieved for fish previously fed 50% PFAD at both optimal and elevated temperatures, the n3/n6 ratios were not fully restored to that of FO fish in the fillet and whole carcass