Small, slender, schooling fishes usually found inshore and over reefs. They usually have somewhat compressed bodies with a terminal mouth, two separate dorsal fins, medium to large eyes and cycloid scales. Pelvic fins are usually abdominal, and the pectoral fins may be high on the body. Marine species usually inhabit coastal seas and are often silvery with a bright silvery stripe along their sides. Some brightly-coloured freshwater species are very popular aquarium fishes. Species range in length from 2 to 44 cm, although most are less than 15 cm.
Hardyheads and their allies are pelagic, forming schools in shallow marine, estuarine and freshwater environments worldwide. They are food for many other fishes, and are used as bait by recreational anglers or in commercial fisheries.
The order comprises 10 families, five of which are found in Australian waters. Three atheriniform families, the Hardyheads (Atherinidae), Blue-eyes (Pseudomugilidae) and Rainbowfishes (Melanotaeniidae) form an important part of Australia’s freshwater fish fauna.
Aarn & Ivantsoff, W. 1997. Descriptive anatomy of Cairnsichthys rhombosomoides and Iriatherina werneri (Teleostei: Atheriniformes), and a phylogenetic analysis of Melanotaeniidae. Ichthyological Explorations of Freshwaters 8(2): 107–250.
Dyer, B.S. & Chernoff, B. 1996. Phylogenetic relationships among atheriniform fishes (Teleostei: Atherinomorpha). Zoological Journal of the Linnean Society of London 177: 1–69.
Nelson, J.S. 2006. Fishes of the World. Hoboken, New Jersey : John Wiley & Sons, Inc. 601 pp.
Parenti, L. 1984. On the relationships of phallostethid fishes (Atherinomorpha), with notes on the anatomy of Phallostethus dunckeri Regan, 1913. American Museum Novitates 2779: 1–12.
Saeed, B., Ivantsoff, W. & Crowley, L.E.L.M. 1994. Systematic relationships of atheriniform families within division I of the series Atherinomorpha (Acanthopterygii) with relevant historical perspectives. Journal of Ichthyology 34(9): 27-72 [original in Russian in Voprosy Ikhtiologii 34(5): 579-610.