McCosker's Flasher Wrasse

Paracheilinus mccoskeri

Also known as McCosker's Wrasse, McCosker Wrasse

SaltwaterFish

McCosker's Flasher Wrasse (Paracheilinus mccoskeri) — jeyre · CC BY 4.0

Care at a glance

Temperature: 72–79°F (22–26°C)
pH: 8.1–8.4
Adult size: 3.1 in (8 cm)
Minimum tank: 55 gal (208 L)
Temperament: Peaceful
Social behavior: Social
Swim level: Middle
Difficulty: Easy
Breeding: Hard
Rarity: Common
Reef safe: Reef safe
Origin: Indo-Pacific reefs, from the western Indian Ocean to Fiji
Family: Labridae

Overview

Peaceful and completely reef safe, spending its time picking zooplankton from the water column rather than bothering corals or invertebrates. It is best kept as a single male, ideally with two or three females, since males spar with rival males of their own or similar flasher wrasse species. Feed enriched mysis, brine shrimp, and other small meaty foods several times a day. Do not forget the tight lid: like all flasher and fairy wrasses, it will jump given the chance.

In the wild

Lives over outer reef slopes, rubble, and algae beds from the western Indian Ocean to Fiji at depths of 5–50 m. In the aquarium it needs at least 208 litres (55 gallons) of mostly open swimming space above live rock, since it spends most of the day hovering and displaying rather than perching on the rockwork. A completely sealed lid is essential, since this species is a strong and accurate jumper.

Good to know

Paracheilinus mccoskeri is a protogynous hermaphrodite. The terminal male develops an orange-red body with iridescent blue horizontal stripes, a yellow belly, and an elongated first ray on the dorsal fin used in display, while females and juveniles stay a duller orange with faint purple lines near the head. Adults reach about 8 cm. Like several other reef wrasses, it sleeps wrapped in a self-secreted mucous cocoon at night.

Did you know

The flashing in this fish's name is a real courtship move: the male erects his dorsal and anal fins to full spread and pulses through his brightest colors in quick bursts while darting around a female, a display that lasts only seconds at a time but repeats over and over around dawn and dusk.