This week we have a reef-dweller with some impressive eye makeup: the arc-eye hawkfish (Paracirrhites arcatus).
Arc-eye hawkfish, also called ringeye hawkfish, are variably colored and named after the horseshoe-shaped markings behind their eyes. Other markings include three short orange bars within a pale blue area on the lower part of the gill cover, and usually a broad pale stripe along the rear of the lateral line. This lateral stripe is thought to be used for communicating with other nearby hawkfish, especially when pairing up to spawn. It has been recorded to reach 8 inches (20cm) in length, however 5 inches (12cm) is more common. Dark and light color morphs of this species occur together, each inhabiting different basaltic and coral microhabitats a few meters apart. These hawkfish are solitary, found in Indo-Pacific tropical lagoons and seaward reefs at depths of about 3-110 feet (1-33 m) where they perch among reef rocks and branching stony coral such as Pocillopora, Stylophora and Acropora.
Arc-eyes are found in the aquarium trade but must be added to reef tanks with caution as they can grow to be very territorial and can eat small fish and invertebrates. They do best with larger fish that can hold their own and larger coral colonies that can handle their perching behavior.
Sources and further reading:
• https://www.georgiaaquarium.org/animal/arc-eye-hawkfish/
• https://www.fishbase.se/ComNames/CommonNameSearchList.php?CommonName=Ring-eyed+hawkfish
• https://fishesofaustralia.net.au/home/species/440#moreinfo
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