Granulated isopods are native to Spain, they like to burrow and also appreciate some drier areas and good ventilation in thier enclosure, so they may not be the ideal ispod for a moist dart frog vivarium for example. They breed relatively rapidly so one starter culture should be enough to give you continous supply over time unless you have quite hungry vivarium inhabitants of course. Having a high calcium content due to their calcarious exo-skeleton woodlice also make excellent live food for reptiles and amphibians.