Blacksmith, Chromis punctipinnis

The Blacksmith, Chromis punctipinnis, whose common Spanish name is castañeta herrera, is a species in the Damselfish or Pomacentridae Family, known collectively as castañetas and jaquetas in Mexico. Globally, there are 84 species in the genus Chromis, eight of which are found in Mexican waters, five in the Atlantic and three in the Pacific.

The Blacksmiths have oblong and compressed bodies that are widest at the dorsal fin origin and taper toward the tail; their body depth is 33% to 37% of standard length. They are very dark dorsally, being blackish with a blue tinge and transition to a lighter blue-gray ventrally. Their scales have black spots from the mid-body to the caudal fin and their caudal and dorsal fins also have black spots. Most fish have a blue border on their anal, caudal, and dorsal fins. Juveniles are more brightly colored than adults and are blue-gray transitioning to yellow-orange at the rear. Their anal fin has two spines and 10 to 12 rays; their caudal fin is forked with pointed lobes; and their dorsal fin has 13 spines and 11 or 12 rays. Their body is covered with large scales.

The Blacksmiths are found inshore and demersal in and around steep banks and rocky reefs and in kelp forests at depths up to 200 feet. They also frequent man-made structures including oil platforms, bridge pilings, docks, and piers. They reach a maximum length of 30.5 cm (12.0 inches). Adults consume algae and zooplankton whereas juveniles eat small crustaceans and juvenile squid. They are preyed upon by larger fish, numerous sea birds, and various marine mammals including the California Sea Lion and harbor seals. They are non-migratory and highly territorial and will aggressively attack intruders. They have a symbiotic relationship with the Señorita, Oxyjulis californica, which provide them with cleaning services. They are known to retreat in close knit aggregations and rest in rocky crevices during the night. Juveniles are pelagic and travel in schools. Reproduction is oviparous with distinct pairings during breeding. Eggs are demersal and attach to the substrate. Males guard and aerate the eggs until they hatch.

In Mexican waters the Blacksmiths have a limited distribution being found from Guerrero Negro northward along the central and northwest coasts of Baja.

Due to its coloration and body profile, the Blacksmith cannot be confused with any other species.

The Blacksmiths are considered an excellent food fish and sold commercially on a limited basis due to their small size. They are difficult to hook via hook and line and many are taken by spearfishermen. From a conservation perspective they are considered of Least Concern, as they are abundant throughout their range and appear to be resilient to coastal development.

Blacksmith, Chromis punctipinnis. Fish caught from coastal waters off Avalon, Catalina Island, California, August 2012. Length: 17.8 cm (7.0 inches).

Blacksmith, Chromis punctipinnis. Underwater photo taken in coastal waters off La Jolla, CA, September 2017. Length: 20.0 cm (7.9 inches). Photo courtesy of Bob Hillis, Ivins, UT.