The thread pipefish (Kyonemichthys rumengani), also known by its Japanese standard name Hari-youji,[3] is a species of pipefish native to the Pacific Ocean around Indonesia, where it is found at depths from 15 to 20 m (49 to 66 ft).

Kyonemichthys rumengani was originally described in 2007 based on an adult female specimen collected in the Lembeh Strait, Sulawesi.

[4] Originally it was thought to be related to the pygmy pipehorse genera Acentronura & Idiotropiscis based on morphological similarities, but mitochondrial genetic analyses have found that Kyonemichthys is instead a sister taxon to Urocampus, forming a clade which excludes the phylogenetically distant Acentronura, Idiotropiscis, and Siokunichthys.

[3] First discovered in Indonesia, Kyonemichthys rumengani appears to be widespread throughout the Indo-Pacific.

[3][5] It is found in mixed habitats on shallow coastal reefs & has been observed orienting itself by using bryozoans, hydroids & debris as holdfasts.