Tank Mates: Other peaceful tankmates such as shrimp gobies, coral gobies, and firefish.
The McCosker's Flasher Wrasse (Paracheilinus mccoskeri) is a truly stunning species; a generally peaceful disposition combined with hardiness and the added benefit of staying small makes P. mccoskeri truly one of the best suited wrasses for keeping in a reef aquarium. They grow to a size of approximately 3 inches in length. P. mccoskeri are protogynous hermaphrodites; depending on social interactions, wrasses that are born as female can and will turn to males in as little as 10 to 14 days. P. mccoskeri should be kept in a minimum aquarium size of a 20gal Long (likely larger if you intend to keep a harem) fitted with a tight lid. Generalist carnivores, P. mccoskeri readily accept a varied diet of prepared foods. Like all flasher wrasses, P. mccoskeri has a high metabolism, and should be fed several small meals a day rather than one or two large meals.
Optimal conditions for P. mccoskeri are; pH 8.1-8.4; salinity 1.020-1.025; and temperature 72-78 degrees F.