A growing number of patent applications are relevant for aquaculture and the fish breeding industry. Patent law is general in form and is seldom adapted to single areas of innovation. It was initially created for the purpose of granting exclusive rights to technical inventions, on the understanding that higher animals, food production and pharmaceuticals were too important for mankind to be included under exclusive private rights. Now that patent law is increasingly invoked in the aquaculture sector, the question arises: how will the law apply to this particular field of innovation? As patent law has the potential to alter the legal conditions for competition and investments in aquaculture, it deserves more attention from policy-makers, fish breeders and fish farmers. This article presents the EPO and Norwegian practice, as a basis for comparing the situation in the USA and Canada with that in Europe. It looks at patentability for product patents and process patents; and the scope of the rights conferred from each of these types of patents as applied to the aquaculture sector. It reviews the most recent patent decision of the Norwegian Supreme Court which concerns the grant of a patent to a fish feed - Histidin. Finally, it presents practice from the Norwegian Ethical Advisory Committee for patent applications relevant to aquaculture.