While this fish is easily confused with Cirrhilabrus lanceolatus due to its sharply angular (AKA lanceolate) tail, genetic analysis shows C.isosceles is actually not related to C.lanceolatus but rather Cirrilabrus of the C.lunatus complex (C.cf. lunatus, C.brunneus, and C.squirei). Several specimens have been sold through the aquarium trade (sometimes identified as C.cf lanceolatus).
The new fairy wrasse species is described in the latest publication of the Journal of the Ocean Science Foundation by “Lemon” Yi-Kai Tea, Hiroshi Senou, and Brian Greene – familiar names to many aquarists. The paper is open access and features a lot of beautiful photographic comparisons with other Cirrhilabrus wrasses.