In Nile tilapia males are of greater size than females. In terms of fish shape preferences may vary, but in any case ascertaining whether relative body dimensions may be altered by selection is of interest. Using the Malaysian GIFT data set we conducted a study with the aim of estimating genetic parameters, especially focusing on the genetic correlation between trait expressions in both sexes and among measurements of body size (Nguyen et al., 2007). Body weight, length, depth and width data at harvest from 12,308 individuals, progeny of 232 sires and 340 dams were analyzed by restricted maximum likelihood methods fitting a multi-trait animal model