Pearlfishes

_{-- P e a r l f i s h e s --} _{click on the question number for the answer}
Q 1.
	What is the “pearlfish?”
Q 2.
	Can you please give me some information concerning a species of eel-like fish which inhabits the cavity of the sea cucumber?
Q 3.
	While visiting the Florida Keys I found a large sea cucumber in shallow water alongside the Overseas Highway. Shortly after placing the animal in a bucket of sea water I discovered, to my surprise, that a beautiful little fish was swimming about in the bucket. Could it have come out of the sea cucumber? The fish was long and slender and silver in color.
Q 4.
	I read about a pearlfish that lives inside sea cucumbers. Is there only one species of pearlfish?


_{-- a n s w e r s a b o u t P e a r l f i s h e s --}
	Q&A 1.	What is the “pearlfish?”
	This tiny eel-like fish, Fierasfer affinis, is most often found living within the body cavity of the holothurian or sea cucumber. It is not a parasite but merely seeks shelter within the sea cucumber, venturing forth to feed upon small organisms quite independently of its host. Pearlfishes also live at times within the shells of mollusks, and occasionally the body of one is discovered completely enclosed in a layer of mother-of-pearl which is laid down by the mollusk. The cause of this is not well understood.
go back to Questions
	Q&A 2.	Can you please give me some information concerning a species of eel-like fish which inhabits the cavity of the sea cucumber? British Columbia, Canada
	The eel-like fishes that inhabit the body cavities of sea cucumbers are generally called pearlfishes and are placed in the single family Carapidae. This is a fairly small group of fishes found around the world in tropical waters, but most abundant in the Indo-Pacific. There is only one widespread species in the western Atlantic Ocean but this is probably the best known in the group. Its scientific name is Carapus bermudensis. These fishes have nothing to do with the true eels but beyond that their systematic position is uncertain. The most recent review of this group was by D. C. Arnold and appeared in 1956 as Vol. 4, No.6, of the Bulletin of the British Museum (Natural History), Zoology. This report should be in the library of the University of British Columbia.
go back to Questions
	Q&A 3.	While visiting the Florida Keys I found a large sea cucumber in shallow water alongside the Overseas Highway. Shortly after placing the animal in a bucket of sea water I discovered, to my surprise, that a beautiful little fish was swimming about in the bucket. Could it have come out of the sea cucumber? The fish was long and slender and silver in color. Chattanooga, Tennessee
	Carapus bermudensis, one of the pearlfishes, commonly lives inside sea cucumbers of the tropical western Atlantic. The slim, iridescent fish has been found within three different species of sea cucumbers by investigators at Miami's Institute of Marine Science. The pearlfish enters and leaves the holothurian by way of the anus. Generally it makes its entry tail-first. The fish apparently does not harm the cucumber, and it sometimes leaves its home at night to feed on tiny crustaceans in the water. Related species of pearlflshes are found in Mediterranean and Indo-Pacific waters. In the Pacific they sometimes inhabit pearl oysters and starfishes as well as holothurians. For an article on pearlfishes (including photographs of them entering and leaving a sea cucumber) see Pacific Discovery, May-June, 1965.
go back to Questions
	Q&A 4.	I read about a pearlfish that lives inside sea cucumbers. Is there only one species of pearlfish? Baltimore, Maryland
	Pearlfishes belong to the family Carapidae. Depending on the classification, there are two subfamilies, seven to eight genera, and 28 to 31 species of these tropical and subtropical fishes. Some pearlfishes are free living, but most live commensally with sea cucumbers, starfishes, sea urchins, bivalves, or tunicates. Some of these fishes live inside pearl oysters and may become encased in the nacre like a pearl-thus, the common name pear1fish. Certain pearlfishes leave their hosts regularly and feed on small crustaceans. Others consume food ingested by their host. However, some of these fishes are parasitic and feed on the gonads and gills of their hosts. Pearlfishes are long, thin, and eellike. Their single dorsal and anal fills run almost the entire length of their scaleless bodies, which end in a sharp, pointed tail. These fishes vary in length depending on the species and on the size of their host. Most pearlfishes enter their host tailfirst, although some enter headfirst.
go back to Questions


	Rosenstiel School of Marine & Atmospheric Science Library University of Miami, FL USA 4600 Rickenbacker Causeway, Miami, Florida 33149 Phone: 305 421 4060 Fax: 305 421 9306 E-mail: libcirc@rsmas.miami.edu		go to the top