The Hourglass triplefin (Enneapterygius elegans) (also known as the Elegant triplefin in the United Kingdom) is a species of triplefin blenny in the genus Enneapterygius. It was originally described by W.C.H. Peters as a species of Tripterygium, in 1876, but was reassigned to Enneapterygius by W. Holleman in 1986. It is a tropical blenny known from reefs across the western central Indian to the central Pacific Ocean, and swims at a depth range of 0-12 metres. Male hourglass triplefins can reach a maximum length of 4 centimetres. The blenny gets its common name from an hourglass-shaped marking on its body.