Q. I need your help in identifying a beautiful wrasse I recently purchased. I can't seem to find it in the Burgess Atlas of Marine Fish or any other source I know. The common name is velvet wrasse, and it has red blotches on the flanks, a red tail (slightly spiked in the center), a purplish gray body, yellow dorsal, pectoral and ventral fins, and a yellow anal fin edged in purple. Can you give me a definite identification and some information on its care and behavior? Also, does this wrasse wrap itself in a mucus membrane at night?

A. The fish you have had the good fortune of acquiring is a male Cirrhilabrus scottorum, known commonly as Scott's velvet or Scott's fairy wrasse. And, it just happens to be one of my favorite fish! A female of this species is pictured in the first edition of the Burgess Atlas (yellow cover), but is listed simply as Cirrhilabrus sp. (page 435).

Scott's fairy wrasse is a wide ranging species, distributed from the Pitcairn Islands to Australia's Great Barrier Reef. There is some geographical variation in the color pattern. For example, male specimens from the Cook Islands are more gaudy and colorful than specimens from Tahiti.

Females are not as colorful as males, and are thus less often exported. Like the males, their color can vary somewhat from one area to the next, but they usually have an olive-green back with traces of blue and purple, and a yellowish-white area below the pectoral fins. They also have a bright blue area on top of the head, a red tail and yellowish-orange dorsal and anal fins. Juveniles are similar to the females, but they have a dark spot on the base of the tail fin and rows of pinkish white spots along the sides. Males of this species attain a maximum length of approximately 6 inches, while females reach 4½ inches.

This species is similar to the black margin fairy wrasse, Cirrhilabrus melanomarginatus (see first edition of Burgess Atlas, page 434). It ranges from the Philippines to Taiwan and differs from Scott's fairy wrasse in that it lacks the yellow color on the front of the head, as well as a red tail fin. The black margin fairy wrasse is rare in the U.S. aquarium fish trade. However, there are numerous other species that do show up regularly. One of the most common is the red-finned fairy wrasse (Cirrhilabrus rubripinnis). This species is usually sold as the red parrotfish. I have found Scott's fairy wrasse to be regularly imported by only one wholesaler. So, if your local aquarium store happens to order from this supplier, you may see this fish frequently.

Scott's fairy wrasse is most common on the outer reef face, in water ranging from 10 to 130 feet in depth. Like most members of the genus, it occurs in small groups consisting mainly of females and juveniles, which hang in the water just above the bottom and feed on passing zooplankton. The larger males will swim as high as 10 feet above the bottom and perform flashy displays at females and rival males by erecting the dorsal and anal fins. They have been observed to spawn in pairs. The male and female will dash into the water column and release eggs and sperm at the top of their spawning ascent.

Fairy wrasses do form a mucus cocoon at night. Studies on parrotfishes, which also form a mucus sheath, have demonstrated that by enveloping their bodies in slime they may prevent olfactory stimuli from reaching nocturnal predators hunting nearby.

I have kept several of these gorgeous fish and have found them to be quite hardy once they acclimate to aquarium life. They should be placed in a large tank (55-gallon tank or larger) with plenty of hiding places. They usually take shelter for several days before they come out to investigate their new home.

When they come out from hiding it is important that they are not bullied by their tankmates and that there is limited human activity both inside and outside of the aquarium. If either of these conditions exists, your fairy wrasse may never adjust to captive living. It is also important that you have a cover on top of the tank to prevent them from jumping out. If you want to keep the tank top open to allow for better gas exchange, make a PVC frame to fit on top of your aquarium and attach fiberglass screening to it. A night light — such as a small 8- or 15-watt incandescent bulb — mounted over the tank will help prevent these suicidal aerial acrobatics when the other tank lights are extinguished.

Once they acclimate, fairy wrasses can be quite boisterous and are very adept at defending themselves. They will aggressively feed on most frozen foods, although live foods, such as brine shrimp and black worms, may aid in getting reluctant individuals to eat. They should be fed a varied diet that includes finely chopped fresh seafoods, such as shrimp, clam and squid. Brine shrimp is not a good staple food for this wrasse, or any marine fish, for that matter. It is important that fairy wrasses are fed at least once a day. If they are not, they will slowly lose weight and perish.

As far as tankmates for your fairy wrasse are concerned, cardinalfishes, anthias, pygmy angelfishes, jawfishes, other nonaggressive wrasses, butterflyfishes, small tangs, gobies, blennies and mandarin fishes are all suitable. Do not keep them with groupers, larger dottybacks, larger angelfishes, triggerfishes and pufferfishes.

Unless you have a big tank (135 gallons or larger), it is also risky to place two males in an aquarium together. If you want to keep more than one fairy wrasse, try maintaining a harem consisting of one male and several females. In order to avoid fighting between individuals, it is important to introduce them simultaneously or to add the females first, and then shortly after add the more aggressive male.

They are great fish for the reef aquarium. The only invertebrates they may bother are small, delicate shrimp, like the anemone shrimp (Periclemenes spp.).