| Damselfish are small fish (generally three to six inches) with an oval or “perch-like” appearance. The most distinctive feature of the Pomacentriadae family is a single nostril on each side of the snout, instead of the usual two. While there are over 315 species of damselfish found worldwide, only 14 species reside in the tropical waters of the Western Atlantic. Four species are responsible for the aggressive reputation of damselfish: Cocoa, Threespot, Dusky and Longfin. The Cocoa and Threespot are similar in appearance as are the Dusky and Longfin damselfish. Threespot damselfish have a yellow crescent above their eyes. Cocoa damselfish have dark areas around their eyes. Longfin damselfish can be distinguished from the Dusky damselfish by their elongated and pointed dorsal and anal fins which extend past the base of the tail. |
| One of the most abundant and best known damselfish is the Sergeant Major, which has markings similar to the military insignia. The male Sergeant Major becomes dark blue to purple during courtship and while guarding egg clusters. While the Sergeant Major is often seen, the Night Sergeant species is rarely observed. Other damselfish species include the beaugregory, bicolor and yellow tail damselfish. |
| Members of the genus Chromis are also part of the damselfish family. The brown chromis and blue chromis are most frequently seen. Both species are elongated and have deeply forked tails. They like to feed together with Creole Wrasse. Sunshinefish, Purple Reeffish and Yellowtail Reeffish are chromis that inhabit deeper reefs and more closely resemble other damselfish in shape. They reside in small groups near the bottom of the reef. |
| Energetic damselfish are perhaps the most territorial fish on the reef. These homesteading fish spend their day tending to and protecting their private algae patch which is highly coveted by parrotfish, surgeonfish and wrasse. They dart back and forth and take nips out of any intruder invading their territory regardless of its size. While the nipping attacks easily repel a single large invader, the palm-sized damselfish are no match for a horde of intruders. The Blue Tang has found a strategy to defeat the damselfish. Late in the afternoon, Blue Tang congregate in a large group and attack a single damselfish garden. The garden is usually destroyed in less than a minute. Though this action may be perceived as detrimental, scientists found that this promotes a healthy condition by preventing algae from smothering the reef. Defended territories are stable throughout time with one generation after another tending the same sites. |
