News / Species Spotlight / Species Spotlight - Guam Chromis (Pomachromis guamensis) (11/09/16)

Species Spotlight - Guam Chromis (Pomachromis guamensis)

Species Spotlight -Guam Chromis (Pomachromis guamensis)

The island of Guam is part of a long chain of island stretching from Tokyo to Palau and is home to a surprisingly large number of species found nowhere else, including todays spotlight: the Guam Chromis. Because of the remoteness of these reefs, we dont often get to see these endemic fishes in the aquarium trade, as relatively little collection takes place here. Until the recent discovery of the Mango Angelfish (Centropyge shepardi) from the northern Philippines, it was one of the least seen members of its genus. Another rarity is the Yellow-crowned Butterflyfish (Chaetodon flavocoronatus), a beautiful deepwater species that fetches princely sums when it gets collected.

The only other species that is collected with any regularity is Richardsons Reef-damsel (P. richardsoni), a darker fish known mostly from the South Pacific and the Ryukyu Islands. Theres also a species from Polynesia with a beautiful white and black body, P. fuscidorsalis, and a seldom seen species found just to the south of Guam in the Caroline and Marshall Islands, P. exilis. This fish is a bit similar to our friend from Guam but differs in having less yellow in the fins and a dark blotch near the tail.

But the forgotten fish from these isles is poor Pomachromis guamensis, an attractively colored fish with a peaceful disposition. While it may be fairly uncommon in aquariums, it is said to be one of the most abundant fishes in its preferred habitat. Youll find this damsel in large schools along seaward reefs, from 3-33 meters deep, where they feed upon zooplankton brought in from the open ocean. The small genus Pomachromis is seemingly restricted to these sorts of environments, with scattered records from across the Indo-Pacific.

Youll be hard-pressed to find much information about the Guam Damselfish in captivity. Given what we know of their behavior and ecology on the reef, there is relatively little concern that Pomachromis will ever turn into the pugnacious piscine terrors that the Family Pomacentridae is known for. The truly bellicose damsels are, without exception, all algae grazers that defend territories, hence the jerk attitudes they often possess. On the other hand, these graceful beauties are more like anthias, gently swimming about in search of a bite to eat. As such, always try to keep your Pomachromis in a groupthe bigger, the betterand feed a varied diet of frozen and dry foods.