Database of intraspecific variation in proximate composition and energy density data for 55 species of fish. Variables: Species; Ref (original reference for data); Median.Latitude (approximate median latitude of sample collection); Median.Longitude (approximate median longitude of sample collection) Capture.Year (year of sample collection); Julian.Median (median julian day (1-365) of sample collection); Julian.Range (length in days of the period over which samples were collected;) N.sample (number of fish per sample, if N > 1 data are composite sample); (Fish Total Length (mm); p.Water (% water); p.Protein (% protein); p.Lipid (% lipid); p.Ash (% ash); EnergyDensity.kJ/g (Energy density of fish [kJ per g wet weight]); L_calc (0 if fish length taken from paper, 1 if calculated from weight using weight length relationship); EDtype ("paper" = energy density taken from paper, "ProLip" = calculated from proximate composition data on % protien and % lipid, "LipOnly" = estimated from % lipid data alone)