Koi Angelfish

Pterophyllum scalare

Animalia›Chordata›Actinopterygii›Cichlidae

📍 Amazon Basin, South America

A captive-bred colour morph with a bold red-orange, white, and black marbled pattern reminiscent of koi pond fish. Each individual is uniquely marked. Hardy and one of the most popular angelfish varieties in the hobby. Same care requirements as other P. scalare varieties.

Size6"

Min Tank30g

School2+

semi-aggressive

Zonemid

Care Guide

Diet

Feed high-quality cichlid pellets as a staple once daily, supplemented 3-4 times weekly with frozen bloodworms, brine shrimp, or daphnia to promote coloration and health. Occasional flake food is acceptable, but pellets should comprise 70% of the diet. Vary food types to ensure balanced nutrition and prevent dietary boredom.

Behavior

Koi Angelfish are mid-water swimmers that exhibit semi-aggressive behavior, particularly during breeding season or when defending territory. They are curious and interactive with their environment, often recognizing their keeper at feeding time. While generally peaceful toward smaller fish, they may nip at long-finned species or consume very small fish; they are best kept in pairs or small groups in adequately sized tanks.

Breeding

Breeding in captivity is moderately difficult and requires pristine water conditions (pH 6.0–6.5, temperature 26–28°C) and a dedicated breeding pair. Angelfish are substrate spawners that lay eggs on flat surfaces and exhibit strong parental care, defending fry aggressively. Separating the breeding pair and fry into a dedicated tank significantly increases success rates; expect 200–500 fry per spawn.

Tank Mates

Neon Tetra

Small size makes them potential prey; keep in large schools to reduce predation risk

caution

Cardinal Tetra

Similar water parameters and mid-water swimming; larger than Neons, reducing predation risk

good

Rummy Nose Tetra

Schooling fish with compatible water requirements; keep in groups of 6+

good

Bristlenose Pleco

Peaceful algae eater that occupies different tank zone; nocturnal, minimizing interaction

excellent

Amano Shrimp

May be eaten if very small; larger adults generally safe but monitor closely

caution

Common Diseases

Ich (Ichthyophthirius multifiliis)

Symptoms

White spots on body and fins, rapid gill movement, lethargy, rubbing against objects

Treatment

Raise temperature gradually to 28–30°C, perform 25% water changes daily, use aquarium salt (1 tsp per 5 gallons) or commercial ich treatment; maintain for 10–14 days

Fin Rot

Symptoms

Frayed or deteriorating fin edges, discoloration, fin loss progressing toward body

Treatment

Improve water quality with frequent 25% water changes, reduce stocking density, treat with antibacterial medication (e.g., tetracycline) if severe; ensure temperature stays 26–28°C

Hole-in-the-Head (Hexamita/Lateral Line Erosion)

Symptoms

Pits or holes along lateral line and head, loss of appetite, white stringy feces

Treatment

Perform 50% water changes every 2–3 days, improve diet with quality foods and vitamin supplements, treat with metronidazole if available; maintain excellent water quality

Angelfish Virus (Iridovirus)

Symptoms

Lethargy, loss of appetite, darkening of body, swollen abdomen, sudden death

Treatment

No cure available; isolate infected fish immediately to prevent spread, maintain optimal water conditions to support immune system, consider euthanasia if condition worsens