in marine larvae can comprise the first 2-3 months post hatch, the larvae rely solely on the innate immune system, whilst the adaptive arm is not fully established[7]. This limits the number of potential treatments as well as prophylactic methods against pathogens as vaccinations are not applicable until the acquired llmmune system is matured and antibiotics are problematic due to environmental aspects. However, the use of immunomodulators in larval culture could present a potential method to increase immunity and sur- vival as they enhance the non-specific, innate immune system 18,9] The application of immunomodulators has been widely studied in juvenile and adult fish(see Ref. [10] for review). A limited number of studies, however, have focused on early life stages 11-16]. Various routes of administration of immunomodulators to fish have been proposed, for example via feed, bath and injection Due to the small size of fish larvae the latter method is not