Species Description…

Scientific Name: Apogon leptacanthus

Common Name: Threadfin Cardinalfish

Species Group: Cardinalfish

Habitat: Reef Safe

Care Level: Beginner

Temperament: Peaceful

Diet Type: Carnivore

Role in Aquarium: Schooling Fish

Max Fish Length: 2.5 (inches)

Min Aquarium Size: 30 (gallons)

Native Range: Indo-Pacific, including Indonesia, the Philippines, and the Great Barrier Reef

Apogon Leptacanthus - The Threadfin Cardinalfish

Apogon Leptacanthus (The Threadfin Cardinalfish)

Native to the Indo-Pacific, particularly in sheltered reef areas and lagoons where it seeks protection among coral branches.
Easily recognized by its nearly translucent body with a faint bluish tint and an elongated dorsal fin.
A peaceful schooling species that prefers to live in groups for security and comfort.
Highly favored by aquarists due to its calm nature, striking appearance, and compatibility with reef setups.
Plays an essential role in reef ecosystems by controlling populations of small invertebrates and zooplankton.

Primarily carnivorous, feeding on small planktonic organisms and microcrustaceans in the wild.
Readily consumes frozen and live foods, including mysis shrimp, brine shrimp, and copepods.
Can gradually adapt to high-quality marine flakes and pellets with consistent feeding routines.
Multiple small feedings per day are recommended due to their high metabolism and constant activity.
Supplementing their diet with vitamin-enriched food enhances their immune system and coloration.

Typically inhabits coral reefs, preferring areas with branching coral where they can seek refuge from predators.
Prefers stable water conditions with gentle to moderate water movement to mimic natural ocean currents.
Aquarium setups should include live rock structures, caves, and shaded hiding spaces for comfort.
Thrives in mature reef tanks with diverse coral growth and plenty of swimming areas.
Providing a structured aquascape encourages natural behaviors such as schooling and darting between coral branches.

Optimal water temperature range: 74-80°F (23-27°C) for maintaining active behavior and good health.
Ideal pH balance: 8.1-8.4, with a salinity range of 1.020-1.025 to replicate natural reef conditions.
Requires a clean, well-maintained aquarium with high-quality filtration to prevent ammonia buildup.
Regular water changes and monitoring of water parameters help keep stress levels low.
Providing a peaceful environment with low aggression levels enhances their longevity and overall well-being.

An excellent choice for community reef tanks due to its non-aggressive nature.
Compatible with other peaceful fish, including gobies, wrasses, tangs, and small angelfish.
Best kept in groups of five or more to encourage their natural schooling instincts.
Should not be housed with aggressive or predatory species that may cause stress or view them as prey.
Pairs well with invertebrates such as shrimp and small crabs, as they do not pose a threat to these organisms.

Typically found hovering in midwater, often forming synchronized schools that move in unison.
Displays a calm and steady swimming pattern, often darting into coral crevices when startled.
Becomes more active under subdued lighting, making them an attractive addition to evening-lit aquariums.
Prefers to remain close to cover, rarely straying too far from coral or rock formations.
Providing a well-structured habitat encourages natural schooling behavior and helps reduce stress.