I am interested in the processes that initiate and maintain biodiversity. In the last five years I have used African cichlid fish as a model system to investigate the evolutionary forces and ecological conditions that lead to the formation of new species and especially to adaptive radiations (ecological adaptation, pre- and postmating isolation barriers, the evolution of mating preferences) with an emphasis on interspecific hybridization as a potential source for genetic variance, evolutionary novelty and functional diversification. More recently, I started working on the ecology and evolution of Swiss endangered fish species (brown trout, grayling). I will focus on the impact of temperature change on sex ratio distortion and the effects of additive genetic variance on various phenotypic and life history traits (stage specific survival, growth rate, smoltification strategy, male colouration, body shape variation, blood hormone levels). The methods I use include comparative methods, phylogenetics, population genetics, breeding experiments, behavioural mate choice experiments, geometric morphometrics and meta-analysis techniques.