Blue-and-Yellow Chromis, Chromis limbaughi

Blue-and-Yellow Chromis, Chromis limbaughi, Juveniles. Underwater photographs taken in coastal waters off Bahia de los Angeles, Baja California, September 2016. Photographs and identification courtesy of Roger Uzun (rogeruzun@gmail.com).

Blue-and-Yellow Chromis, Chromis limbaughi. Underwater photographs taken in coastal waters off Bahia de los Angeles, Baja California, September 2016. Photographs and identification courtesy of Roger Uzun (rogeruzun@gmail.com).

The Blue-and-Yellow Chromis, Chromis limbaughi, is a member of the Damselfish or Pomacentridae Family, also known as Limbaugh’s Damselfish and in Mexico as castañeta Mexicana. Globally, there are eighty-four species in the genus Chromis, of which eight are found in Mexican waters, five in the Atlantic and three in the Pacific Ocean.

The Blue-and-Yellow Chromis has a deep oval body with a depth that is 48% to 52% of standard length. The juveniles are bright blue, transitioning to yellow posteriorly. As they mature they lose the yellow coloration within the tail and the overall blue coloration darkens to purple. Their heads can be bright blue. Their anal, caudal and dorsal fins are yellow and their caudal fin is whitish. The head has a small protrusible oblique mouth that opens in the front with 2 rows of teeth. Their anal fin has 2 spines and 11 rays; their caudal fin is forked with rounded lobes; their dorsal fin has 13 spines and 11 or 12 rays; and, their pectoral fins have 18 or 19 rays. They have 27 to 31 gill rakers. They are covered with large rough scales. Their lateral line is incomplete and ends under the edge of the dorsal fin base.

The Blue-and-Yellow Chromis is normally found in groups, either small or large. They are a non-migratory species normally found in a rocky reef environment at depths up to 75 m (250 feet). They reach a maximum of 11.3 cm (4.4 inches) in length. They are found on the surface of the reefs but will move in aggregations into the water column to feed on plankton. The juveniles stay close to the bottom for protection. They will take shelter when frightened. Reproduction is oviparous with distinct pairing of individuals. The eggs are distributed demersally, adhere to the substrate and are guarded by the males. The eggs hatch into planktonic larvae in three days. The Blue-and-Yellow Chromis 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. They have lifespans of up to 15 years in captivity.

The adult Blue-and-Yellow Chromis is very easy to identify due to its markings. The juveniles are similar in appearance to the juvenile Bumphead Damselfish, Microspathodon bairdii (orange ventrally) and the juvenile Silverstripe Chromis, Chromis alta (lack yellow tail).

The Blue-and-Yellow Chromis is a resident of Mexican waters of the Pacific Ocean but is limited to lower two thirds of the Sea of Cortez and the Revillagigedos Islands.

From a conservation perspective the Blue-and-Yellow Chromis is currently considered to be of Least Concern with stable, widely distributed populations. They are utilized by the aquarium trade, being non-aggressive, hardy, easy to maintain, and long lived. They are protected by the Mexican Federal Government due to their commercial significance within the aquarium trade.