Cosmocampus banneri (roughridge pipefish, or Banner's pipefish) is a species of marine fish of the family Syngnathidae.

It is found from the Red Sea and Western Indian Ocean to Fiji, the Marshall Islands, and the Ryukyu Islands.

[1] It lives in coral reefs at depths of 2-30m, where it can grow to lengths of 5.8 cm.

[1] This species is ovoviviparous,[2] with males carrying eggs in a brood pouch until giving birth to live young.

[3] The specific name honours Albert Henry Banner (1914–1985), an American carcinologist who was an expert in alpheid shrimps.