Cyanobacteria (blue-green algae) are a group of ancient prokaryotic organisms dating back between three and four billion years.¹ They have been attributed with oxygenating the earth’s atmosphere² but, since the anthropogenic euthrophication of lakes, ponds and oceans, they have become synonymous with water hygiene issues.³ This is due to the alteration of the nutrient composition of their habitat to one which is optimal for growth (or blooms). Cyanobacterial blooms may simply cause foul tastes and odours,⁴ but they can also lead to the production of toxic secondary metabolites poisonous to humans and animals upon ingestion.⁵ NZ has yet to suffer a human fatality, but the deaths of several dogs in Wellington was attributed to homoanatoxin-a 1 (Chart 1) from a Phormidium species.⁶