Extrapolation from ecologically sim- ple, laboratory tests to ecologically complex natural habitats has been a major challenge for assessing the ecological risks of transgenic fish (Devlin et al. 2006; Devlin et al. 2007). Trans- genic fish risk assessments require data from experiments test- ing clearly identified mechanisms for changes in invasive traits that include key components of ecological complexity, such as these with zebra danios. This is particularly important as trans- genic Atlantic salmon Salmo salar and other transgenic fishes approach commercialization.