Longspine Cardinalfish

The Longspine Cardinalfish is a delicate and enchanting species prized for its translucent body adorned with subtle neon blue-green accents along its fins and body. At a maximum size of just two and a half inches, this diminutive cardinalfish is one of the smaller members of its family, making it perfectly suited for nano reef aquariums. Its ghostly, semi-transparent appearance allows the viewer to see its internal organs and skeletal structure, giving it an otherworldly beauty that is quite unlike any other commonly kept marine fish.

In the wild, Longspine Cardinalfish are found in large aggregations among branching Acropora corals and other sheltered reef habitats throughout the Western Pacific. They form dense schools that hover just above the coral branches during the day, retreating deeper into the coral framework at night. This schooling behavior is one of their most appealing characteristics in the aquarium, where a group of five or more creates a mesmerizing display as they drift together in gentle coordination.

Despite their fragile appearance, Longspine Cardinalfish are reasonably hardy once acclimated to the aquarium. They are completely reef-safe, peaceful, and pose no threat to corals or invertebrates. Their small size and gentle nature make them ideal companions for other small, peaceful species in nano and micro reef setups. They do require consistent water quality and regular feeding to thrive, as their small body size leaves little room for energy reserves.