Mating with close relatives often reduces offspring fitness due to inbreeding depression. Importantly, environmental stress can also lower fitness. One widespread factor creating a stressful environment is low food availability. In particular, limited food during juvenile growth is known to reduce adult fitness. Crucially, this type of negative environmental effect might be greater for inbred individuals due to the increased expression of deleterious recessive alleles that affect performance. Sexually selected traits offer an ideal test case to investigate the alleged interaction between inbreeding and environmental stress because they are often influenced independently by both inbreeding and body condition. Here we use the mosquitofish (Gambusia holbrooki –an invasive species that inhabits Australia) to investigate the interacting effects of inbreeding and stressful environments on traits that are important in both pre- and post-copulatory sexual selection.