Porcellio haasi (high yellow isopod)

This is a large species typically found in dry mountainous areas along the Eastern coast of Spain, where they hide within and along calcareous rock formations. Despite the common belief within the hobby, they do not prefer dry conditions, and keeping them in such conditions can be fatal. They require access to areas with higher moisture levels, particularly mancae. This closely resembles their natural conditions, as humidity inside rock crevices can be much higher than the surrounding ambient humidity. However, like many of the large Porcellio species, they are susceptible to death from excessively moist substrate and stale humid air. The key to successfully keeping them is to ensure that the proper air circulation is present to prevent stagnant, humid conditions within their enclosure.