The Paracheilinus mccoskeri is commonly known as McCosker's Flasher wrasse. When compared with other members of wrasse fish family McCosker's Flasher wrasse are the most attractive with vibrant colours. So they are the most sought after ornamental fish. The flasher wrasses are chromatically blessed Paracheilinus genus. The resplendent male McCosker's Flasher wrasse found in the Indian Ocean has a radiating orange colour on its back and sides with bright blue bands against yellow fins. Though McCosker's Flasher wrasse has a striking resemblance with Carpenter's flasher wrasse (Paracheilinus carpenteri).They can be easily distinguished by the presence of one elongated dorsal filament in the former. McCosker's Flasher wrasse also has a longer nonfilamentous dorsal rays and lower number of gill rakers. Male flashers draw more attention than female counterparts as they flash. This phenomenon of flashing is rarely observed as they are small sized and stay in deeper areas. These active swimmers after this display swiftly vanish into the deep lying coral reefs.
Young McCosker's Flasher wrasse members prefer to swim about in solitary or small groups. It is commonly observed that male McCosker's Flasher fish swim around groups of female species and attract them by flashing their radiant chromic fins. Male fish usually swim too deep and quickly swim from one place to another in search of female groups.
The McCosker's Flasher wrasse is a hardy fish that requires only medium maintenance. It should be introduced only to a less aggressive fish only tank, as they are generally peace loving fish. Usually, McCosker's Flasher wrasse is not aggressive towards nonrelated species. An ideal tank set up would be to introduce one male fish with 3 or more female McCosker's Flasher wrasse. So, they can be kept comfortably with other fish. As these fish have a peculiar habit of burying themselves while sleeping and when intimidated by predators, the aquarium should be provided with sand bed. They have good reef compatibility.
Maximum Size: The McCosker's Flasher fish is observed to grow to a maximum size of 4 inches.
General Size Specifications: They are generally available in the size of about 2 to 3 inches.
Minimum Tank Size: The tank size should be at least 20 gallons, with lot of space for the McCosker’s Flasher fish to hide and swim. Water quality should be high. (SG 1.020 - 1.025, pH 8.1 - 8.4, Temp. 72 - 78° F).
Habitat: Range: They are found in Indo-Pacific region, Fiji and Indonesia
Feeding and Diet: The McCosker’s Flasher wrasse is a carnivorous and feeds on fish, scallop, shrimp, squid, clam and planktonic.