PCR has been used successfully to identify hard-to-isolate fish pathogens, such as Mycobacterium
spp. in sea bass (Dicentrarchus labrax) and M. chelonei in a cichlid oscar (Astronotus ocellatus) . Moreover, PCR has been useful with distinguishing different species from within the same genus, such as Lactococcus garvieae from L. lactis , from related genera, i.e. L. garvieae, S. difficilis, S. iniae and S. parauberis , and with an admirable level of specificity