Saltwater Aquarist

Pajama Cardinalfish

(Sphaeramia nematoptera)

Pajama Cardinalfish

Species Description…

Scientific Name: Sphaeramia nematoptera
Common Name: Pajama Cardinalfish
Species Group: Cardinalfish
Habitat: Reef Safe
Care Level: Beginner
Temperament: Peaceful
Diet Type: Carnivore
Role in Aquarium: Community Fish
Max Fish Length: 3.5 (inches)
Min Aquarium Size: 30 (gallons)
Native Range: Indo-Pacific

Overview

  • Native to the Indo-Pacific, commonly found in lagoons, seagrass beds, and sheltered reef areas.
  • Recognized for its unique coloration, featuring a silvery body, dark vertical band, and red-spotted tail.
  • A peaceful and social species that thrives in groups, making it an excellent addition to community aquariums.
  • Primarily nocturnal, becoming more active in the evening while seeking food.
  • Best suited for aquariums with stable water conditions, live rock formations, and low to moderate lighting.

Feeding

  • Carnivorous, primarily feeding on small crustaceans, plankton, and marine invertebrates in the wild.
  • Thrives on a diet of frozen mysis shrimp, brine shrimp, copepods, and high-quality marine pellets.
  • Readily accepts prepared foods and benefits from regular small feedings throughout the day.
  • Should be fed at least twice daily to maintain energy levels and encourage natural foraging behavior.
  • A varied diet enhances coloration and supports a strong immune system.

Habitat

  • Prefers calm reef environments with overhangs, coral formations, and sheltered rock structures.
  • Frequently found schooling near branching corals or seagrass beds for protection.
  • Aquarium setups should include live rock to provide natural hiding spaces and support social interactions.
  • Requires stable water parameters and effective filtration to ensure optimal health.
  • Providing dim lighting or shaded areas encourages its natural nocturnal behavior.

Fish Care

  • Optimal water temperature: 74-80°F (23-27°C) for maintaining health and activity.
  • Preferred pH range: 8.1-8.4, with a salinity level of 1.020-1.025.
  • Requires regular water changes and consistent maintenance to prevent water quality deterioration.
  • Reef-safe and does not pose a threat to corals or invertebrates.
  • Providing a peaceful environment with minimal aggression from tankmates supports longevity.

Compatibility

  • Highly social and best kept in small groups to exhibit natural schooling behavior.
  • Compatible with clownfish, gobies, wrasses, and other peaceful reef-safe species.
  • Should not be housed with overly aggressive fish that may stress or outcompete it for food.
  • Best suited for a well-balanced reef aquarium with non-aggressive tankmates.
  • Providing multiple rock formations and shaded areas ensures a comfortable habitat.

Aquarium Behavior

  • A calm and social species that enjoys swimming in groups and resting near coral structures.
  • Frequently observed schooling near rock crevices or darting between aquarium decorations.
  • More confident in a well-established aquarium with plenty of shelter and tankmates.
  • Providing dim lighting or moonlights encourages nighttime activity and foraging.
  • Over time, it may become accustomed to its caretaker and actively respond during feeding times.