🚚 Dry goods ship Australia-wide 🐠 Livestock — buy online, collect in store 🧪 In-store water analysis
Eastwood AquariumMarine only
SavedCart
Home  /  Fish profiles  /  Koran Angel
Koran Angel (Pomacanthus semicirculatus)

Koran Angel

Pomacanthus semicirculatus
Not Reef SafeLarge AngelHardy For Its GroupLong-Lived
Family
Angelfish (Large)
Care level
Intermediate
Temperament
Semi-aggressive
Reef safe
Not reef safe
Max size
40 cm
Min tank
750 L · 198 gal
Origin
Indo-West Pacific
Diet
Omnivore
Food
Angelfish preparations with sponge, Nori, Spirulina, Mysis, Chopped seafood
Currently out of stock →Join the waiting list

Overview

The Koran Angel (Pomacanthus semicirculatus) — also called the Semicircle or Half-circled Angelfish — is one of the great transformation fish of the hobby. Juveniles are deep blue-to-black, crossed by narrow white and electric-blue semicircular bands that arc across the body like flowing script (the origin of the 'Koran' name). As they mature, that pattern dissolves into an entirely different adult look: an olive-to-yellow-green body densely speckled and edged in sapphire blue, with blue-trimmed fins, trailing filaments and a yellowish tail.

It's a large, intelligent, regal fish that becomes bold and personable, learning to recognise its keeper and cruise its territory with real presence.

Two honest headlines shape how you keep it. First, it's one of the hardier large angels and adapts well to aquarium life, which makes it a good entry point into big angels for an intermediate keeper. Second, it grows large, lives for well over a decade, and is not a coral-tank fish — so it belongs in a spacious fish-only or FOWLR system you're prepared to commit to long term.

Compatibility

Toward non-angelfish the Koran is relatively peaceful — juveniles in particular are shy and reclusive — but it becomes increasingly territorial as it matures, and it's genuinely aggressive toward other angels, especially of its own genus or similar appearance. The rule is one angel per tank, and because it's one of the largest of its group and will claim the tank as its own, it's best added last.

Given a large enough system, it coexists well with other robust, active fish of similar temperament — tangs, larger wrasses, and the like — and even some peaceful species if there's ample space. Avoid other large angels, dwarf angels, and overly aggressive tankmates, and provide plenty of rockwork so everyone has territory and boltholes.

Health & quarantine

For a large angel, the Koran is refreshingly hardy — it adapts readily and usually eats most foods with gusto, which is a big part of why it's considered one of the better big angels to start with. Even so, large angels are prone to ich and other parasites, especially through the stress of collection and introduction, so a proper quarantine period and a slow, drip acclimation are strongly recommended, and a UV steriliser and good protein skimmer are worthwhile support. Juveniles can be a little more delicate and shy, so choose a healthy, actively feeding fish. Keep it in a large, mature system with pristine, well-oxygenated water and robust filtration, and it's a long-term resident — often living 15 to 20 years.

Frequently asked questions

Is the Koran Angel reef safe?
No. It nips at soft and stony coral polyps, clam mantles and other sessile invertebrates as part of its natural grazing, and it becomes bolder about it as it matures. Keep it in a fish-only or FOWLR setup rather than a coral display — this is the key thing to understand before buying one.
How big does it get, and what tank does it need?
It reaches around 40 cm — a genuinely large fish. A juvenile can start in roughly 450 litres to grow and establish territory, but plan for at least 750 litres (and ideally more) for an adult. It's often sold small, so it's easy to underestimate the space it will eventually demand.
Is it a good large angel for a first-timer?
It's one of the better choices. Among the big Pomacanthus angels, the Koran is notably hardy, adapts well and usually feeds readily, which makes it a sensible entry into large angels for an intermediate keeper with the tank space. It's a considered purchase, but a forgiving one as big angels go.
Can I keep it with other angelfish?
Generally no — keep it as the only angel in the tank. It's territorial toward other angels, especially its own genus or similar-looking species, and gets more so with age. Mixing angels only works in very large systems with careful planning, and even then it's risky.
Why do juveniles and adults look so different?
It's a natural developmental change common to large Pomacanthus angels. Juveniles wear the blue-and-white semicircular 'script' pattern, which gradually transforms into the speckled green-blue adult colouration as the fish matures. Watching that transformation is one of the main reasons keepers buy them as juveniles.
Do I need to quarantine it?
Yes, it's strongly recommended. Large angels are susceptible to ich and other parasites, and the acclimation period is the riskiest window. Quarantine lets you observe, treat if needed, and confirm strong feeding before it joins your display — a UV steriliser and good skimmer help keep it healthy longer term.

Care guidance is drawn from our own experience — every fish is an individual, so treat it as a starting point, not a guarantee. Not sure if a species suits your tank? Come ask us in store. New to the terms? Read the care-terms glossary.