Corythoichthys amplexus, known commonly as the brown-banded pipefish, is a species of marine fish in the family Syngnathidae.

[3] The skin has a base colour of light tan with broad reddish-brown bands on the body, each 3–4 rings wide, which lie across the side and dorsal surfaces, occasionally these are divided to form two closely set bands, and sometimes they are indistinct on the posterior third of the tail.

The head lacks prominent stripes behind eye and the ventral surface of anterior trunk rings is blotched with dark brown in males, while often being marked with small paired spots in females.

The eggs mass consists of 2–17 transverse rows within a gelatinous matrix.

[4] The brown-banded pipefish is widespread throughout the tropical waters of the Indo-West Pacific region, from the eastern coast of Africa to the western Pacific north to the Ryukyu Islands to south the Great Barrier Reef.