Barspot Cardinalfish, Apogon retrosella

Barspot Cardinalfish, Apogon retrosella. Fish caught from coastal waters of San José del Cabo Rió, Baja California Sur, April 2022. Length: 5.9 cm (2.3 inches). Catch, photograph and identification courtesy of Luke Ovgard, Klamath Falls, Oregon.

Barspot Cardinalfish, Apogon retrosella. Underwater photographs taken in Zihuantanejo Bay, Guerrero, March 2018 and December 2019. Photographs courtesy of Ron Woheau, Zihuantanejo.

Barspot Cardinalfish, Apogon retrosella. Underwater photograph taken off Point Palmilla, Baja California Sur, October 2019. Photograph courtesy of Bob Hillis, Ivins, Utah.

The Barspot Cardinalfish, Apogon retrosella, is a member of the Cardinalfish or Apogonidae Family, and is known in Mexico as cardenal de Cortés. Globally, there are one hundred ninety species in the genus Apogon, of which seventeen are found in Mexican waters, twelve in the Atlantic and five in the Pacific Ocean.

The Barspot Cardinalfish has a small, laterally compressed, and oblong body. They are reddish-pink overall with a black spot at the middle of their caudal fin base, a black bar below their second dorsal fin, and a large black spot with white lines that runs from their snout through their eyes to the end of their gill covers. Their head is large with a short pointed snout, large eyes, and a large oblique mouth equipped with bands of small teeth. Their anal fin has 2 spines and 7 rays; their caudal fin is concave; their first dorsal fin has 6 spines; their second dorsal fin has 1 spine and 9 or 10 rays; and, their pectoral fins have 12 rays. They have 11 to 13 gill rakers on their lower arch. They are covered with rough scales. Their lateral line is complete and extends into the tail base.

The Barspot Cardinalfish is found within rocky reefs at depths up to 61 m (200 feet). They reach a maximum of 10.0 cm (3.9 inches) in length. They are nocturnal predators emerging at night and forming small schools while remaining secluded during the day. They consume small fish and small invertebrates including crab and shrimp. They are one of the rare marine species exhibiting oral brooding; males incubate the fertilized eggs in their mouth for several days before releasing hundreds of larvae measuring 2 to 4 mm into the ocean. Larvae remain in planktonic form for several weeks before developing into juveniles. The Barspot 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.

The Barspot Cardinalfish is a resident of all Mexican waters of the Pacific Ocean.

The Barspot Cardinalfish is a straightforward identification  due to its black markings, although somewhat similar in shape and color to several other Cardinalfish.

The Barspot Cardinalfish from a conservation perspective are current considered to be of Least Concern, with a wide distribution and stable populations. They are utilized by the aquarium trade on a limited level being easy to maintain, however, they are not available at adequate levels in the wild and are aggressive tank mates known to consume their fry.