Yellowtail filaria (Philometroides seriolae)

Body looks reddish orange due to sucking fish blood.

A large parasite sometimes having a body length exceeding 50 cm.

Parasitizing muscles and body cavities, coiling themselves.

The body is long and narrow but the end is not pointed.  Yellowish white mucus may be accumulated in the cavity made as a result of parasitism.  Parasitism often occurs in early spring but less in autumn and winter.