A comprehensive taxonomic survey of Chrysochromulina was undertaken in 52 samples from southern Tasmanian coastal waters. Scale morphology of both field samples and enrichment cultures was examined using transmission electron microscopy. Twenty-eight known species of Chrysochromulina were recorded. These included C. adriatica , C. alifera , C. apheles , C. brevifilum , C. chiton , C. cyathophora , C. ephippium , C. ericina , C. hirta , C. leadbeateri , C. mantoniae , C. minor , C. novae - zelandiae , C. pachycylindra , C. parkeae , C. polylepis , C. pringsheimii , C. pyramidosa , C. simplex , C. spinifera , and Chrysochromulina sp. (“eyelash”). There were seven new records for Australian waters: C. acantha, C. aff. brachycylindra , C. aff. camella , C. fragaria , C. mactra , C. scutellum and C. aff vexillifera . All species, except C. novae-zelandiae , had been previously reported from the northern hemisphere. A further nine undescribed species are documented. However, lack of complete cells prevented new species descriptions. Two known toxic species, Chysochromulina polylepis and C. leadbeateri , responsible for massive fish kills in Scandinavia, were found in this survey. Toxicity testing of six Chrysochromulina species isolated from Tasmanian waters ( C. acantha , C. apheles , C. hirta , C. scutellum , C. simplex , Chrysochromulina sp. [“eyelash”]) was undertaken, using larval brine shrimp ( Artemia ) bioassays. None of the strains tested was found to be toxic.