How to spot the Half-circled Angelfish when scuba diving
Pomacanthus semicirculatus
Found in all tropical and subtropical oceans worldwide. Marine angelfishes (family Pomacanthidae) consist of approximately 86 species across 8 genera. Greatest diversity occurs in the Indo-Pacific region, particularly in the Coral Triangle. Different species have varying ranges from small geographic areas to widespread distribution.
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Visible year-round in tropical coral reef environments. Diurnal (active during daylight), making them readily observable on day dives.
Tropical to subtropical waters, typically 24-30°C (75-86°F). A few species tolerate slightly cooler temperatures.
Found on coral reefs and rocky outcrops from shallow waters down to about 70m, though most commonly encountered at recreational diving depths (5-30m). Juveniles often have different coloration and may inhabit distinct areas from adults. Different species occupy different niches: Emperor angelfish often on reef slopes, French angelfish commonly near sponges, Pygmy angels in reef crevices. Larger species may be territorial. Common across healthy coral reef systems worldwide, with highest diversity in Indonesia, Philippines, Papua New Guinea, and the Great Barrier Reef. Caribbean species diversity is lower but includes distinctive species like the Queen, French, and Gray angelfish.

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Worldwide observation of the Half-circled Angelfish
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Data sources
- Photos: Wikimedia Commons
- Distribution and specie data: GBIF (Global Biodiversity Information Facility)
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