Dusky Cardinalfish, Phaeoptyx pigmentaria

Dusky Cardinalfish, Phaeoptyx pigmentaria. Fish caught from coastal waters off Long Island, New York, November 2022. Length: 4.8 cm (1.9 inches). Catch, photograph and identification courtesy of James Lafontaine, Long Island, New York.

The Dusky Cardinalfish, Phaeoptyx pigmentaria, is a member of the Cardinalfish or Apogonidae Family, that is also known as the Peppered Cardinalfish and the Pigmented Cardinalfish and in Mexico as cardinal estrellado, cardenal pigmentado and cardenal prieto. Globally, there are three species in the genus Phaeoptyx all three are found in Mexican waters of the Atlantic Ocean.

The Dusky Cardinalfish has an oblong compressed body. They are pinkish to bronze in color and the snout has a yellowish tinge. They have a dark bar under the eye. The head and body are covered with uniformed sized, evenly spaced, dark specks, one per scale. They have a dark bar across the caudal base. Some fish have one or two rows of dark dots along the base of the anal and dorsal fins. They have a large head and a short snout with large round eyes and a large oblique mouth that opens at the front that is equipped with small teeth with enlarged teeth at the front of the top jaws and on the sides of the lower jaws. Their anal fin has two spines and eight rays; their caudal fin is concave; their first dorsal fin as six spines; their second dorsal fin has one spine and nine rays; and, their pectoral fins have 11 to 13 rays. They have 11 to 13 lower gill rakers. Their gill cover is serrated. Their body is covered with rough scales. They have a complete lateral line that extends onto the caudal fin base.

The Dusky Cardinalfish is found within coral and rocky reefs and gravel or shell substrate at depths up to 50 m (165 feet). They reach a maximum of 8.0 cm (3.1 inches) in length. They are nocturnal predators emerging at night and forming small schools while remaining secluded during the day. They consume phytoplankton and zooplankton. They are found in close proximity to feeding basket stars, massive sponges and seagrass beds. They are one of the rare marine species exhibiting oral brooding. The Dusky Cardinalfish is poorly studied with very limited information available about their lifestyle and behavioral patterns including specific details on age, growth, longevity, movement patterns, diet, habitat use, and reproduction.

In Mexican waters the Dusky Cardinalfish is a resident of all Mexican waters of the Atlantic Ocean including the Gulf of Mexico and the Caribbean with the exception that they are absent from Tuxpan, Veracruz, north to the Texas border in extreme northwest section of the Gulf.

The Dusky Cardinalfish can be confused with the Bridle Cardinalfish, Apogon aurolineatus (body plain, two to four dark lines radiate from eyes), the Freckled Cardinalfish, Phaeoptyx conklini (anal fin and second dorsal fin have a dark stripe at the base), the Sponge Cardinalfish, Phaeoptyx xenus (yellow snout, plain body) and the Striped Cardinalfish, Apogon robbyi (yellow fins).

From a conservation perspective the Dusky Cardinalfish are currently considered to be of Least Concern with stable widely distributed populations. Their populations are also being adversely affected by the recent introduction of the Red Lionfish, Pterois volitans, which competes for prey and space. The Dusky Cardinalfish are utilized by the aquarium trade at a nominal level.