Blacksail snake mackerel

The blacksail snake mackerel (Thyrsitoides marleyi), known also as the black snoek, is a species of snake mackerel found in the Indo-Pacific from shallow water to a depth of at least 400 m (1,300 ft) where they appear to prefer slopes on seamounts and ridges. They are known for making diel vertical migrations to near-surface waters at night, feeding on fish, squid and crustaceans. This species reaches a total length of 2 m (6.6 ft) though most are around 1 m (3.3 ft). This species is of minor importance to local commercial fisheries.

It is at the only member of the genus Thyrsitoides, making the genus monotypic. However, a second extinct species, T. zarahoustrae Arambourg, 1967, is known from the Late Eocene-aged Pabdeh Formation of Iran and potentially the Early Oligocene of Romania.