Koran angelfish or koi angelfish?
These two names are easy to mix up, and they refer to completely different fish.
- Koran angelfish (Pomacanthus semicirculatus) is a saltwater species from the Indo-Pacific. Juveniles are deep blue with curved white markings, and adults turn olive to yellowish with blue edging.
- Koi angelfish is a color variety of the freshwater angelfish (Pterophyllum scalare), with orange, white and black patches resembling koi.
The rest of this article is mainly about the saltwater Koran angelfish, with a short section on koi angelfish. Because this site’s cluster is about freshwater fish, note that the Koran angelfish needs a marine aquarium.
Koran angelfish tank size
A Koran angelfish grows large, reaching up to about 15 inches (38 cm), and may live for many years. Retailers and care sources generally agree that the adult needs a very large tank:
- One retailer lists a minimum of 180 gallons.
- Other care sources suggest considerably more, so recommendations vary.
Because recommendations vary, treat 180 gallons as the floor and consider larger if you can. A tank length of around 6 to 7 feet is often suggested so the fish has room to swim along the length of the aquascape. Smaller tanks may be fine for a while, but a fish that is going to outgrow them is a problem for you or the fish later.
Juvenile growth and temporary tanks
Juveniles are sold at a small size and look manageable. One source suggests a 75 to 100 gallon tank can work as a temporary grow-out setup. The color change from blue juvenile to adult pattern is reported to begin at roughly 4 to 6 inches. Plan the permanent tank before you buy, since moving a fish later adds stress and often means rehoming. Also be aware that angelfish do poorly in unstable new tanks, and they are usually added to mature systems.
Why footprint and rockwork matter
Koran angelfish graze on algae and encrusting life, so established live rock is useful. They also need open swimming lanes. A good layout offers:
- Plenty of rockwork with caves for hiding and grazing.
- Open space in front of the rock.
- Strong filtration and stable salinity, with regular water testing and water changes.
Koran angelfish are typically described as not fully reef safe, as they may nip at corals and other invertebrates.
How big will koi angelfish get?
Freshwater koi angelfish are far smaller than Koran angelfish. Freshwater angelfish are tall-bodied fish, and adults commonly reach roughly 6 inches in body length, with fins making them much taller. Because of their height, a tall tank is preferred. Many keepers suggest at least 29 gallons for a pair or small group, with larger tanks for more fish, but guidelines vary. Look at the tank’s height as well as its volume.
Price
Prices vary widely with size, seller and whether the fish was quarantined and eating well. Juveniles are often cheaper than adults, and adults that have been grown out and are feeding well typically cost more. Koi angelfish, being a freshwater aquarium variety, generally cost much less than a marine Koran angelfish. Because prices change, check current listings from reputable sellers rather than relying on a fixed figure.
Tank mates and fish to avoid
Koran angelfish (saltwater). They can be territorial, especially as they mature. They are often kept alone, and housing with other large angelfish is only suggested in very large tanks. Avoid small or timid fish that they may bully, and be cautious with corals, clams and sponges.
Koi and other freshwater angelfish. Common guidance includes:
- Avoid very small fish such as neon tetras, which may be eaten by adult angelfish.
- Avoid fin-nippers, like tiger barbs, which can damage long fins.
- Avoid boisterous or highly aggressive fish that can outcompete or bully them.
How often to feed
Koran angelfish are omnivores. One retailer recommends feeding 2 to 3 times a day, with a mix of marine algae, spirulina, mysis and brine shrimp, chopped seafood and sponge-based angelfish foods. Freshwater angelfish are commonly fed once or twice a day in small portions of what they can finish in a few minutes. Overfeeding fouls the water for both types of fish. For a freshwater comparison on feeding frequency, see our guide on how to feed discus fish.
Before you buy
- Decide whether you want the saltwater Koran or a freshwater angelfish.
- For a Koran, plan on a tank of at least 180 gallons and likely more.
- Quarantine the fish before introducing it to the display tank.
- Make sure the fish is already feeding well in the store.