Saltwater Fish
Apogon cyanosoma
Apogon cyanosoma - Orange-Lined Cardinalfish

Apogon cyanosoma (Orange-Lined Cardinalfish)

Species Description…

Scientific Name: Apogon cyanosoma
Common Name: Orange-Lined Cardinalfish
Species Group: Cardinalfish
Habitat: Reef Safe
Care Level: Beginner
Temperament: Peaceful
Diet Type: Carnivore
Role in Aquarium: Community Fish
Max Fish Length: 3 (inches)
Min Aquarium Size: 20 (gallons)
Native Range: Indo-Pacific

Overview

  • Commonly found in the Indo-Pacific region, often inhabiting coral reefs and lagoons.
  • Easily recognized by its pale body adorned with multiple yellow horizontal stripes running from head to tail.
  • A nocturnal species that prefers to remain hidden during the day, becoming more active at night.
  • Frequently found in small groups or pairs, sheltering among coral branches or rocky overhangs.

Feeding

  • Carnivorous, primarily preying on planktonic organisms, small crustaceans, and zooplankton.
  • Accepts a variety of live and frozen foods, including brine shrimp, mysis shrimp, and copepods.
  • Can adapt to eating high-quality marine flakes and pellets when introduced gradually.
  • Prefers multiple small meals throughout the day, especially during dimly lit periods.

Habitat

  • Typically resides in coral-rich environments, hiding among branching corals and crevices for protection.
  • Prefers stable water conditions with a moderate water current.
  • Aquariums should include ample live rock and shaded hiding areas to create a comfortable setting.
  • Thrives in reef tanks with plenty of shelter while allowing open swimming areas.

Fish Care

  • Optimal water temperature: 72-78°F (22-26°C).
  • Ideal pH range: 8.1-8.4, with a salinity level of 1.020-1.025.
  • Requires clean water conditions with strong filtration to maintain its health.
  • Ammonia and nitrite levels should be kept at a minimum to prevent stress-related illnesses.
  • Providing a dim environment with subdued lighting helps mimic their natural deepwater habitat.

Compatibility

  • A peaceful species that thrives in community reef tanks with other non-aggressive fish.
  • Compatible with tangs, gobies, wrasses, and other small to medium-sized reef-safe species.
  • Should not be housed with large or aggressive fish that may see them as prey.
  • Best kept in small groups or pairs, as they exhibit natural schooling behavior.

Aquarium Behavior

  • Nocturnal by nature, often retreating to caves and coral crevices during daylight hours.
  • Becomes more active in the evening, exploring the aquarium and searching for food.
  • Forms small schools in the wild but can be kept singly or in pairs in a home aquarium.
  • Providing plenty of hiding spaces and a structured tank setup encourages natural behaviors.