Lagenophrys cochinensis is a ciliate episymbiont of sphaeromatid isopods, including Sphaeroma quoianum, S. terebrans, S. annadalei, and Exosphaeorma planulum. It is presumed to be native to the Indo-Pacific region, and has been introduced to the northeast Pacific, with S. qouianum and the tropical-subtropical northwest Atlantic with S. terebrans. Lagenophrys cochinensis was described from India, and so far is known from its presumed native range, India, Thailand, Malaysia, Philippine, New Zealand, and presumed introduced regions (S. quoianum, Humboldt Bay (1st Record: 1936), San Francisco Bay, 1973); S. terebrans: (1st Record: Indian River Lagoon, 1973, Florida; Cuba (1994); Venezuela (undated). The sphaeromatiid hosts are wood-borers, so the isopods and their ciliates were probably transported on the hulls of ships. The attached ciliates feed on bacteria and other suspended particles, but impacts on their hosts are not known.