Carmine Triplefin, Axoclinus storeyae

FEMALES:

MALES:

FEMALES and MALES:

LIGHTER MORPH:

Carmine Triplefin, Axoclinus storeyae. An exceptional portfolio of underwater photographs taken in Zihuantanejo Bay, Guerrero, November 2018 to March 2019, courtesy of Ron Woheau, Zihuantanejo. Very productive and greatly appreciated discussions and identification support courtesy of Dr. Phil Hastings, Scripps Institution of Oceanography, La Jolla, California.

The Carmine Triplefin, Axoclinus storeyae, is a member of the Triplefin or Tripterygiidae Family, and are known in Mexico as  tres aletas carmín. Its common name stems from the division of its dorsal fin into three parts, two of which have spines. Globally, there are one hundred forty-five members in the Tripterygiidae Family placed into thirty genera with five known species in the genus Axoclinus, of which three are found in Mexican waters of the Pacific Ocean.

The Carmine Triplefin has a short and robust body. The upper half of their body is brown or greenish and the upper three-fourths of their body has 3 vertical red-brown bars and 4 vertical rows of white spots. They are sexually dimorphic: breeding males have a uniform bright red body with black caudal and first dorsal fins and females are green with a wide black stripe on the base of their tail. Their caudal fin is white with red bars that extend into the tail base. They have a large head covered with spines with small simple cirri on top of their head, one pair over their nostrils, and one pair over their eyes. Their anal fin has 2 spines and 16 to 17 rays; their first dorsal fin has 3 spines; their second dorsal fin has 12 spines; their third dorsal fin has 9 or 10 rays; and, their pelvic fins are serrated. They are covered with small scales except on their head, breast, belly, and pectoral fin base.

The Carmine Triplefin is found in shallow water reef environments around rocks and boulders with abundant algae at depths up to 6 m (18 feet). They reach a maximum of 4.3 cm (1.7 inches) in length. They consume small invertebrates. Reproduction is oviparous with hemispherical eggs that attach themselves to the substrate via sticky threads. The larvae are planktonic. The Carmine Triplefin 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 Carmine Triplefin is a resident of Mexican waters of the Pacific Ocean but has a limited distribution being found from Magdalena Bay, Baja California Sur southward along the southwest coast of the Baja, in the lower half of the Sea of Cortez, and along the coast of the mainland south to Acapulco.

The Carmine Triplefin is straightforward to identify due to its coloration, however, its body structure is similar to that of the Cortez Triplefin, Axoclinus nigricaudus (lacks red coloration, body and tail with 5 wide oblique black bars) and the Panamic Triplefin, Axoclinus lucillae (pectoral fins with pink bars).

From a conservation perspective the Carmine Triplefin is currently considered of Least Concern with stable, widely distributed populations. They are seldom seen by humans and are of limited interest to most.