The fat content and fatty acid compositions of edible muscle of commercially important seawater and freshwater fish species were investigated. The fatty acid compositions of seawater fish species were found to be 25.5-39.4% saturated (SFA), 13.2-29.0% monounsaturated (MUFAs) and 25.2-48.2% polyunsaturated acids (PUFAs), whereas the fatty acid compositions of freshwater fish from Lake Seyhan consisted of 28.0-34.6% saturated (SFA), 10.7-22.7% monounsaturated (MUFAs) and 23.2-43.7% polyunsaturated acids (PUFAs). The proportions of n3 PUFAs of seawater fish (ranging from 22.6 for waker to 44.2% for blue fish) were higher than those of n3 PUFAs of freshwater fish (ranging from 11.5% for North African catfish to 28.4% for zander). However, the levels of n6 PUFAs of seawater fish (ranging from 0.43% for blue fish to 14.4% for sea bass) were lower than those of n6 PUFAs of freshwater fish (ranging from 5.27% for kutum to 16.8% for tench). The results showed that fatty acid profiles of most freshwater fish are basically comparable to those of seawater fish as sources of PUFAs. (c) 2006 Elsevier Ltd. All rights reserved.