Ring-tailed Cardinalfish

The Ring-tailed Cardinalfish is a beautiful and underappreciated species named for the distinctive dark ring or spot at the base of its caudal fin. Its body displays a warm golden to coppery hue with subtle iridescent highlights, making it one of the more colorful cardinalfish species. Found across a broad range throughout the Indo-Pacific, this species is a common inhabitant of sheltered reef areas, lagoons, and harbors where it forms large schools among coral heads and rocky overhangs.

Like all cardinalfish, the Ring-tailed Cardinalfish is primarily nocturnal, spending daylight hours hovering in loose aggregations near protective shelter and becoming more active as darkness falls. In the aquarium, this translates to a fish that is relatively sedentary during the day but comes alive during evening hours when it actively hunts for small food items. Providing a photoperiod with a gradual transition to moonlight or dim blue lighting allows observers to enjoy the species' more active nocturnal behavior.

This species is an excellent choice for beginner marine aquarists due to its hardiness, peaceful disposition, and adaptability to aquarium conditions. It readily accepts a wide variety of prepared foods and is completely reef-safe. The Ring-tailed Cardinalfish thrives when kept in small groups, and its relatively small maximum size of just over four inches makes it appropriate for modestly sized aquariums. It is one of the most forgiving cardinalfish species in terms of water parameter fluctuations.