Natural Habitat: Western Atlantic, from North Carolina to Brazil, including the Gulf of Mexico and the Caribbean Sea.
Size: Up to 3 inches (7.5 cm) in length.
Lifespan: 2-5 years in captivity with proper care.
Aquarium Setup
Tank Size: Minimum of 20 gallons for a small group (3-5 fish).
Water Parameters:
Temperature: 72-78°F (22-26°C)
pH: 8.1-8.4
Specific Gravity: 1.020-1.025
Ammonia/Nitrite: 0 ppm
Nitrate: <20 ppm
Filtration and Aeration:
Strong filtration to maintain water quality.
Moderate water movement, mimicking reef conditions.
Protein skimmer recommended.
Aquascaping:
Provide plenty of hiding spots with live rock.
Ensure there are crevices and caves for the fish to retreat to.
Lighting:
Moderate lighting, as they are often found in shaded reef areas.
Feeding
Diet:
Carnivorous; primarily feed on small invertebrates and zooplankton.
Offer a variety of foods including:
Live and frozen brine shrimp
Mysis shrimp
Finely chopped seafood (e.g., shrimp, squid)
High-quality marine pellets and flakes
Feeding Frequency:
Feed 2-3 times daily in small amounts.
Behavior and Compatibility
Temperament:
Generally peaceful but can be territorial with conspecifics.
Best kept in small groups; avoid keeping solitary individuals.
Tankmates:
Compatible with other peaceful fish.
Avoid large, aggressive species that may prey on them.
Good companions include other small, non-aggressive fish such as gobies, blennies, and some small wrasses.
Breeding
Breeding in Captivity:
Difficult but possible with dedicated effort.
Mouthbrooders: Males carry eggs in their mouths until they hatch.
Requires stable, optimal water conditions and a well-established aquarium.
Separate breeding pair into a dedicated breeding tank to increase chances of survival for fry.
Health and Disease
Common Health Issues:
Susceptible to marine ich and other parasitic infections.
Maintain water quality to prevent stress-related diseases.
Preventative Measures:
Quarantine new additions before introducing them to the main tank.
Regular water changes and tank maintenance.
Treatment:
Use appropriate marine medications in a quarantine tank if needed.
Special Considerations
Cardinalfish are nocturnal feeders; they may be more active during evening and night hours.
Ensure tank mates are not aggressive during feeding times.
Regular observation is key to detecting early signs of stress or illness.
Summary
Apogon compressus, or the cardinalfish, is a beautiful and peaceful addition to a marine aquarium, provided they are given proper care and a stable environment. They thrive in well-established tanks with plenty of hiding places and a varied diet. Regular maintenance and monitoring are crucial to their health and longevity in captivity.
