AbstractSponges are common in coral reefs and provide secondary habitats and shelter to a very diverse associated biota. To examine the symbiotic relationships between crustacean associates and their sponge hosts, the most important step is to collect live crustaceans and sponges for subsequent taxonomic identification as well as for larval rearing and experiments on larval biology. Using sponge-inhabiting barnacles as a model, we describe a set of collection procedures, identification methods, and laboratory-rearing systems for maintaining living barnacles and their host sponges. These methods also permit observing the behavior of the barnacle symbionts, including feeding, mating, as well as larval development and settlement, information that can be applied to the study of host-specificity, larval biology, and host selection.