Koran Angel (Pomacanthus semicirculatus): Breeding Guide
Pomacanthus semicirculatus is a large Indo-Pacific angel that spawns pelagic eggs in the open water column and is not home-bred. Its planktonic larvae drift in the ocean, so this guide describes wild reproduction rather than an aquarium protocol.
Overview
Pomacanthus semicirculatus, the Koran or Semicircle angel, ranges across the Indo-West Pacific from the Red Sea and East Africa to Samoa, north to southern Japan and south to Western Australia. FishBase lists a maximum standard length of about 40 cm and a depth range of roughly 1 to 40 m.
Adults feed on sponges, tunicates and algae, so the species is not reef-safe. Juveniles inhabit shallow protected areas and carry the white half-circle markings that give the fish its common name, while adults prefer coastal reefs with heavy coral growth and are generally solitary or in pairs.
Sexing
Sexes cannot be told apart by external colour. The genus is generally protogynous, with females able to become males, so a pair is usually formed by growing two fish together and letting the dominant individual turn male.
Spawning Behavior & Trigger
Like other large Pomacanthus, this species is oviparous and spawns as pairs that rise off the reef to release eggs and sperm into the open water column. Fertilization is external and the gametes are carried away on the current.
Species-specific timing is not detailed in the consulted sources; related large angels spawn at dusk, so twilight is the expected trigger for pelagic spawning in this species.
Egg & Fry Care
The eggs are pelagic and float up into the plankton, hatching into minute larvae adapted to open-water drift. They require natural ocean micro-plankton during a prolonged larval phase.
FishBase notes that young of this species make excellent, hardy aquarium fish, but that refers to wild-caught juveniles; the consulted sources report no home-rearing of larvae from egg to settlement.
Common Challenges
- Pelagic eggs disperse in open water, so there is no nest or clutch to manage.
- Larvae need micro-plankton first foods that are not available in home systems.
- Adults reach about 40 cm and need very large tanks, complicating broodstock conditioning.