Koi Angelfish Care Guide - Aquarium Setup, Diet & Breeding

Koi Angelfish are a striking cultivated form of the freshwater angelfish, with a tall, laterally compressed body, long trailing fins and a vivid pattern of white, orange and black. The amount of orange and the distribution of dark markings vary considerably between individuals, making each fish subtly different.

Their elegant shape and graceful swimming style have made angelfish a long-standing favourite in home aquariums. Despite their delicate appearance, they are still cichlids and can show confident, territorial behaviour, particularly when forming a pair or defending a spawning site.

In the wild, Pterophyllum scalare inhabit quiet waters shaded by overhanging vegetation and flooded woodland. Their tall bodies allow them to manoeuvre among roots, stems and submerged branches, while their natural coloration helps break up their outline in the dappled light.

Koi Angelfish are captive-bred ornamental fish rather than a naturally occurring wild colour form. They retain the intelligence, social behaviour and breeding instincts of the species, and mature specimens can become impressive centrepieces in a suitably spacious aquarium.

Koi Angelfish are a domestic colour variety of Pterophyllum scalare, a species native to tropical South America. Wild scalare angelfish occur in slow-moving rivers, flooded forests and connected tributaries across parts of the Amazon, Orinoco and Essequibo drainage regions.

A group of Koi Angelfish should be housed in an aquarium of at least 200 litres, with a footprint around 120 cm long by 45 cm wide and plenty of vertical height; a taller aquarium is especially valuable for this deep-bodied species. Use gentle to moderate filtration and leave open swimming space alongside tall plants, driftwood and broad-leaved vegetation that provide cover without crowding the tank. A fine sand or smooth-gravel substrate is suitable, and subdued lighting with shaded areas helps recreate their naturally sheltered habitat.

Adults can reach approximately 15 cm (6 in) in body length and up to 25 cm (10 in) in total height from the top of the dorsal fin to the bottom of the anal fin. Females and males are similar in overall size, although well-conditioned males may become slightly larger and more robust.

Offer a varied omnivorous diet of quality angelfish pellets or flakes, supplemented with frozen or live foods such as bloodworms, brine shrimp, daphnia and mosquito larvae. Small amounts of vegetable matter can also be included through spirulina-based foods or suitably prepared vegetables. Feed modest portions and vary the menu rather than relying on a single food.

Koi Angelfish can live with peaceful, moderately sized community fish such as larger tetras, peaceful barbs, rasboras, Corydoras, larger peaceful catfish, bristlenose plecos and some peaceful dwarf cichlids. Avoid fin-nipping species, highly aggressive cichlids and fish that are small enough to be swallowed, including tiny tetras once the angelfish mature. They may also harass one another or other angelfish if kept in a cramped aquarium, especially when pairs begin breeding.

Koi Angelfish form pairs and deposit their adhesive eggs on broad vertical surfaces such as slate, plant leaves or aquarium equipment. Condition a compatible pair with varied, protein-rich foods, then provide clean, warm, slightly acidic to neutral water. The parents may tend and fan the eggs, although inexperienced pairs often eat their first spawns. Eggs generally hatch after around two to three days, and the free-swimming fry can be raised on newly hatched brine shrimp or a suitable powdered fry food.

Koi Angelfish are difficult to sex reliably outside of breeding condition. Mature males may develop a broader head, a more pronounced forehead and a slightly larger body, while females often appear fuller through the abdomen when carrying eggs; the shape and position of the breeding papilla are the most dependable indicators when a pair is ready to spawn.