Ringtail Cardinalfish
Ringtail Cardinalfish
© François Libert
Fishes · Bony fishes · Cardinals

Ringtail Cardinalfish

Nectamia annularis (Rüppell, 1829)
syn. Apogon annularis, Apogon erdmani, Ostorhynchus annularis
7 cm1-17 mLeast Concern
817

Nectamia annularis, commonly referred to as the tailring cardinalfish, is a marine species within the Apogonidae family, also known as cardinalfishes.

This species is characterized by its relatively small size, reaching a maximum length of approximately 7 cm. The tailring cardinalfish displays an elongated, laterally compressed body with a rounded profile. Notable features include two translucent dorsal fins, a single lateral line, a prominent mouth, and large, rounded eyes. The body exhibits a silvery-grey coloration, accentuated by a distinctive black ring encircling the caudal peduncle.

Habitat distribution for Nectamia annularis includes the tropical waters of the undefined, encompassing regions such as the 🌊 Red Sea, the 🌊 Gulf of Aden, and the 🇲🇻 Maldives. These fish are typically located in shallow marine environments near coral reefs, at depths reaching up to 17 meters (56 feet).

Primarily zooplanktivorous, the tailring cardinalfish feeds predominantly on zooplankton.

Exhibiting nocturnal behavior, this species may feed either solitarily or in small aggregations within shallow waters above coral reefs. During daylight hours, Nectamia annularis commonly seeks refuge within the crevices and caves of coral reefs.

Why it's threatened

This species is not known to be threatened by harvesting for the aquarium trade but may be undergoing localised declines due to habitat degradation. The coral reefs off Eilat are threatened by a number of factors including mariculture effluent, sewage, bilge and ballast water, ship fuel discharge, intense tourism pressure, and discharge of detergents and phosphates. The reefs of Eilat are considered to be in a 'critical state' (Wilkinson 2004), but elsewhere in the range of this species, reefs are likely to be less threatened. Crown of Thorns Starfish is a localized threat. Overall, these localized threats do not appear to be driving rapid population declines (O. Gon pers. comm. 2009).

Threat classification from the IUCN Red List.

Comments

Please, sign in to leave a comment

Continue with a social account — yours will be created automatically.

No comments yet — be the first.

Last Update: June 28, 2026