Carp gudgeons (Eleotridae: Hypseleotris) are the most abundant, widespread and biodiverse freshwater fishes in southeastern Australia, but the unacknowledged presence of multiple cryptic species and hemi-clonal unisexual lineages severely taints all research on this cornerstone group. Our goal is to help correct past taxonomic shortcomings and supply a valid framework for future study, by giving researchers a true picture of the group’s biodiversity plus the means to accurately identify all sexual and unisexual forms in this key group. We used three genetic datasets including allozymes (52 loci), mtDNA (cytochrome b) and ddRADSeq (>10,000 SNP loci) to examine species and lineages across their entire range in southeastern Australia where most habitats contain 2-4 sympatric species and additional hemi-clonal lineages. One key finding was a single sexual population of Lake’s carp gudgeon which is of critical conservation and research concern as every other population examined of Lake’s carp gudgeon are F1 hemi-clonal hybrids. For more details all about this group you'll have to come and see my talk!