This bioactive clean-up crew pack contains one culture of 20+ Trichorhina tomentosa Dwarf White isopods, 15+ P. pruinosus Party Mix isopods, and an 8 oz. culture of Mixed Species springtails on substrate. This combo pack will provide the essential microfauna for your bioactive enclosure up to 55 gallons. For large enclosures more than 60 gallons, the Large Enclosure 60+ gallon Clean-Up Crew pack contains two 8 oz. cultures of Mixed species springtails, 50 Trichorhina tomentosa Dwarf White isopods, and 50 P. pruinosus Party Mix isopods. Other isopods/springtails that do well in bioactive enclosures include any P. pruinosus (Powder Blue, Orange, Oreo Crumble, Orange Cream, Red Koi), Lepidocyrtus fimicolus 24K, Seira dowlingi Silver, Coecobrya communis Tropical/Pink. and P. laevis Gray/Dairy Cow/Milkback/Orange/White Please see shipping details for shipping cost information and live arrival guarantee. Isopods will be shipped in a container of organic peat moss, sphagnum moss, and organic leaf litter. Springtails are shipped in a container of topsoil and peat moss. Both containers can be simply dumped on top of the enclosure's substrate. There is no need to "bury" them in the substrate. A thick layer of leaf litter at all times is the key to a thriving isopod colony.