Koi Angelfish

Looks how to spot one

Scales and fins

The Koi Angelfish has a tall, disc-shaped body with long, flowing dorsal and anal fins and delicate ventral filaments. Its base colour is a shimmering pearl-white or pale gold, overlaid with bold, random blotches of jet black and bright orange or rusty red, often concentrated on the head and back. The pattern is unique to each individual, much like a fingerprint.12

Personality what they are like

Koi Angelfish are generally peaceful and calm, but they become territorial and semi-aggressive once they pair up for breeding. They are curious and often recognise their keeper, swimming to the front of the tank at feeding time. They may nip at long-finned tankmates or eat very small fish, so choose companions carefully.46

Daily activity how busy a day looks

These fish are mid-water swimmers that need plenty of open swimming space with tall plants or driftwood for shelter. They are not overly active but enjoy exploring and hovering among vegetation. Provide a tank with at least 120 cm length and a water depth of 50-60 cm to allow for their tall body shape.13

Grooming and care the hands-on bits

Koi Angelfish are relatively easy to care for but require stable water conditions. Keep the water warm (24-30°C), slightly acidic to neutral (pH 5.0-7.5), and perform regular partial water changes. They do best in a well-planted aquarium with gentle filtration. Avoid keeping them with fin-nipping species like tiger barbs or zebra danios.73

Home where they are happiest

In the wild, Pterophyllum scalare lives in slow-moving, densely vegetated waters of the Amazon basin, such as flooded forests and oxbow lakes. In captivity, provide a tall tank (minimum 120 cm long, 50-60 cm high) with plenty of vertical plants, driftwood, and open swimming areas. They prefer soft, slightly acidic water, though captive-bred fish tolerate a wider range.13

Food basics what goes in the bowl

Koi Angelfish are omnivorous with a carnivorous leaning. In the wild they eat insect larvae, small crustaceans, worms and tiny fish. In the aquarium, offer a varied diet of high-quality cichlid pellets or flakes as a staple, supplemented with frozen or live foods such as bloodworms, brine shrimp, daphnia and tubifex worms. Feed once or twice daily, only as much as they can eat in a few minutes.84

Company who they like around

Koi Angelfish are social and do best in small groups of 5-6 juveniles, but they become territorial when they mature and pair off. They can be kept with other peaceful community fish, but avoid very small fish that can be eaten and fin-nippers. Provide plenty of hiding spots and visual barriers to reduce aggression. They are not suitable for tanks with very aggressive species.54

The story where it all began

The Koi Angelfish is not a wild species but a selectively bred colour variety of the freshwater angelfish, Pterophyllum scalare. It was developed in commercial fish farms, mainly in Asia and the USA, by crossing and selecting for a marbled pattern that resembles the colours of Japanese Koi carp. Unlike the wild silvery form with dark vertical bars, the Koi variety displays a pearl-white or gold base with bold black and orange blotches. This pattern is unique to each fish and is the result of decades of selective breeding. The care requirements are identical to those of the standard angelfish species.12

Recognised by the official bits

FishBase

Recognised as a popular aquarium cichlid with a compressed, disc-shaped body and long dorsal and anal fins.3

Atlarium

Described as a domestic colour variant of Pterophyllum scalare with a pearl-white or pale gold base and black and orange marbling.1

Popularity Very popular among freshwater aquarium hobbyists, especially those who enjoy cichlids with striking colours.5