Influence of salinity has been studied in Euryhaline fishes. Changes in the glycerophospholipid metabolism have been detected during and after adaptation of euryhaline fishes to sea water, diluted sea water or fresh water. Some specific effect of salinity on the phosphatidylserine decarboxylation in gills and N-methylation of the phosphatidylethanolamine in the liver has been described in euryhaline fishes. The implication of sphingomyelin metabolites as transducers of osmosensory signals has been shown in fish gills of euryhaline fishes. The presence of different enzymes of phospholipid metabolism has been correlated with changes of phospholipid metabolism induces by salinity stress.