Cubaris sp Rubber Ducky isopods Native to Thailand, Rubber Ducky isopods prefer high humidity with deep substrate to burrow down into to help molt. Rubber Ducky isopods will spend a decent amount of time fully submerged into the substrate before and after molting. Quite possibly the most famous isopod in the hobby today. Rubber ducky isopods for sale can reach 20mm (0.79 inches) in length. They have small broods ranging from 1-20. Rubber Ducky isopods take a few months to fully acclimate but breed year round once established.