Mites are commonly found on captive invertebrates, yet little is known of their impact on the health of the host. The nature of the association between mites and invertebrate host ranges from harmonic or phoretic to parasitic and, rarely, parasitoid. The assumption is often made for mites seen on select invertebrate hosts that they are innocuous, yet hard data to support such assumptions is usually lacking. The decision to treat or disregard acariasis in invertebrates should be based on identification of the mites and determination of the mite–host relationship, whether through direct observations of the mite on the host or through necropsies of infested hosts.