The three species of Pterophyllum are unusually shaped for cichlids being greatly laterally compressed, with round bodies and elongated triangular dorsal and anal fins.

P. leopoldi fry develop three to eight body stripes, with all but one to five fading away as they mature, whereas P. scalare only has two in true wild form throughout life.

Though angelfish are members of the cichlid family, they are generally peaceful when not mating; however, they still may feed on very small species of fishes.

When the pair is ready to spawn, they choose an appropriate medium upon which to lay the eggs, and spend one or two days picking off detritus and algae from the surface.

Fish infected with Ich exhibit small, white, grain-like spots on their body, fins, and gills.

The primary cause of an Ich outbreak is usually stress, which can result from factors such as poor water quality, sudden temperature changes, or the introduction of new fish without proper quarantine.

[6] To treat Ich, increasing the aquarium's temperature gradually to 78–86 °F (25–30 °C) for a few days can speed up the parasite's life cycle.

The primary causes of fin rot are poor water quality, overcrowding, and physical damage, all of which stress the fish and make them more susceptible to infections.

Fish afflicted with this condition may struggle to maintain their position in the water, often floating upside-down, sinking to the bottom, or swimming at unusual angles.

The causes can be diverse, ranging from overfeeding, constipation, and rapid water temperature changes to physical injury and bacterial infections.

[9] To treat swim bladder disease, it's advised to first fast the fish for 24–48 hours, followed by feeding them a diet of cooked, skinned peas, which can help alleviate constipation.

Bacterial Infections in aquarium fish can manifest in various ways and are caused by harmful bacteria proliferating within the tank.

Symptoms can range from visible ulcers, sores, and red streaks on the fish's body to bloating, erratic swimming, and a loss of appetite.

The primary triggers for bacterial infections often include poor water quality, overcrowded tanks, stress, and injuries.

Specialized antibacterial medications, available at pet and aquarium stores, can be administered based on the specific type of bacterial infection.

For the most part, the original crosses of wild angelfish were not recorded and confusion between the various species of Pterophyllum, especially P. scalare and P. leopoldi, is common.

The result of this is a domestic angelfish that is a true hybrid, with little more than a superficial resemblance to wild Pterophyllum species.