Fish vaccines have been and are evolving parallel to the growing fish farming industries globally. In the 1990s a relatively high dose of 0.2 ml oil-based vaccine could result in severe adverse reactions in the abdominal cavity of injection vaccinated salmon. New vaccines were developed with half that dose, 0.1ml in the early 2000s, with an improved welfare and safety profile. This also included vaccines for other species than salmonids. Up to six bacterial and viral components needed to be added in these vaccines , requiring more research and technology development in order to ensure acceptable efficacy and safety. Based on further RnD , refinement of both downstream and formulation processes involved, PHARMAQ launched the micro dose injection concept in 2008; a 0.05 ml dose volume containing the same antigens. This was the first product of its kind , and the volume en abled vaccination of even smaller fish, while still maintaining efficacy and further improvement of safety. This concept was proven successful and has since been the foundation for most of the Pharmaq vaccines developed across species; Salmon, trout, Atlantic cod, cleaner fish , seabass and bream, tilapia and pangasius. Since 2013 mono- and di-valent vaccines have also been developed with the further reduced dose volume; 0.025ml. These volumes are injected alone or in combination with the micro dose vaccines while still maintaining as low injected volumes as possible. Safe dosing and administration are still fully possible with modern and calibrated injection systems, automated or manual. The development and experiences with the smaller dose volume vaccine concepts across species will be presented and discussed.