Other internal parasites are found living inside fish gills, include encysted adult didymozoid trematodes,[14] a few trichosomoidid nematodes of the genus Huffmanela, including Huffmanela ossicola which lives within the gill bone,[15] and the encysted parasitic turbellarian Paravortex.[16] Various protists and Myxosporea are also parasitic on gills, where they form cysts.