©Anne Hoggett: Atherinomorus lacunosus about 12 cm long schooling near mangroves at Mangrove Beach, Lizard Island. Note irridescent line along upper back and dark spot on upper iris.
©Anne Hoggett: Part of a large school of Atherinomorus lacunosus near mangroves at Mangrove Beach. About 12 cm long.
©Anne Hoggett: Atherinomorus lacunosus about 12 cm long (upper part of image, irridescent line along upper back and dark spot on upper iris) schooling with Herklotsichthys quadrimaculatus (lower part of image, pair of orange spots behind operculum, deeper body) near mangroves at Mangrove Beach, Lizard Island.
Colours
Distinguishing features
A small silvery fish with a large eye and an iridescent stripe along the side of the body, always seen in large schools close to the shoreline. Body length is 4.1 to 5.6 times body depth according to Allen and Erdmann (2012).
Atherinids have two widely-separated dorsal fins and the pectoral fin inserted high on the side.
Size
- Up to 13 cm (length according to Allen and Erdman, 2012)
- Up to 7 cm (Length of specimens commonly observed around Lizard Island.)
Depth range
- Depth range data is not yet available.
Synonyms
Similar taxa
-
Animalia:
Endracht Hardyhead (species: Atherinomorus endrachtensis)
is relatively shorter, length about 4.3 times body depth according to Allen and Erdmann (2012) -
Animalia:
Capricorn Hardyhead (species: Atherinomorus capricornensis)
may or may not be synonymous with Atherinomorus lacunosus according the Fishes of Australia website (accessed 29 Oct 2021).
Distribution
©Atlas of Living Australia: Australian distribution
Distribution and habitat preferences
Pelagic (dwells near the water surface) but aggregates in large schools over reef areas near rocky shorelines and mangroves.
Often found near the mangroves at Mangrove Beach, and can be periodically seen close to rocky shores in other bays of the island.
Behaviour
Hardyheads are plankton feeders, and a major food source for predators when they aggregate near the island in summer. They will jump en masse when attacked, making a spectacular silvery shower.
Web resources
References
References that assist with identification
- Allen and M.V. Erdmann, G.R. (2012). Reef fishes of the East Indies. Volumes I-III in: Reef fishes of the East Indies. Tropical Reef Research, Perth, Australia. LIRS catalog number 90162.
Other references
- Conand, F. (1993). Life history of the silverside Atherinomorous lacunosus (Atherinidae) in New Caledonia, Fish Biology, 42: 851-863. LIRS catalog number 90016.