News / Species Spotlight / Blue-nose Pencil Wrasse (Pseudojuloides kaleidos) (01/16/19)

Blue-nose Pencil Wrasse (Pseudojuloides kaleidos)

Species Spotlight - Blue-nose Pencil Wrasse (Pseudojuloides kaleidos)
There was a time not that long ago when there was just a single species of Pencil Wrasse known from coral reef ecosystems. Pseudojuloides cerasinus was described way back in 1904 from Hawaii, and over the years it was reported from all across the Indo-Pacific, as far west as Africa. It wasnt until 1981 that this would change.

That was the year that John & Helen Randall published their study of this genus, establishing new species for some of the regionally distinct populations in the cerasinus group. There was a bright red one isolated in the Marquesas, P. pyrius (a fish which has rarely been spotted since). There was another unique form from Mauritius which had a much shorter stripe along the side, P. xanthomos. And its only gotten more complicated from there.

In the years since, we saw the African population christened as P. polockorum. In 2017, the representative from the southern parts of Polynesia became P. polynesica, while those elsewhere in the Pacific were recognized as P. splendens. This left the Hawaiian P. cerasinus as an endemic species.

The one region we skipped so far is the rest of the Indian Ocean, the area that includes the Maldives, the Andaman Sea and south towards Bali. This population is also distinct, and it was actually recognized fairly early on when P. kaleidos, the Blue-nose Pencil Wrasse, was described from the Maldives in 1995. So how do we identify this fish?

There are a few distinctive qualities to keep an eye out for. Its most likely to be confused with P. splendidus; the two even hybridize where their ranges overlap in Bali and Christmas Island. The Blue-nose name refers to a blue stripe running along the back, which is usually more pinkish in the Pacific population. Behind the eye is a wide blotch of green (or sometimes greenish-yellow), while in P. splendens there is instead a pair of distinct green lines. The caudal fin is mostly yellow in P. kaleidos (vs having a black posterior band). And, lastly, the sides turn black in terminal males of the Blue-nose and stay green in P. splendens.

As for captive care, Pencil Wrasses have historically had a poor reputation for heartiness. Once acclimated to life in an aquarium, these fishes are no more challenging than other similar wrasses, such as Anampses, Macropharyngodon, or Cirrhilabrus, but there is an initial hurdle to get over. It is always best to purchase specimens which are actively swimming and show an interest in food. Pseudojuloides are zooplanktivores and do best on a mixed diet of meaty foods.

Multiple specimens can be housed together, and its quite possible to mix more than one species from this genus. Compared to most wrasses, Pseudojuloides are exceptionally peaceful and often quite timid. This must be kept in mind when choosing tankmates, as more boisterous labrids can cause a pencil wrasse to spend its time in hiding. And though they are not especially large in size (maximum size is only around 5 inches), they benefit from having ample swimming room. A large reef aquarium makes for an ideal setting.