News / Species Spotlight / Orange Lined Wrasse (Stethojulis balteata) (12/19/18)

Orange Lined Wrasse (Stethojulis balteata)

Species Spotlight - Orange Lined Wrasse (Stethojulis balteata)
Stethojulis wrasses, sometimes known as Ribbon Wrasses, are not a common site in the aquarium trade, despite being a fairly diverse and common genus thats found all across the Indo-Pacific. In the wild, youll see small groups quickly flitting about the reef, sometimes in very shallow coastal habitats, with the colorful males greatly outnumbered by the more camouflaged females and juveniles. As with other labrids, these are protogynous hermaphrodites, with only the largest specimens able to mature into colorful males.

There seem to be three good reasons why these wrasses are underrepresented in aquariums. Firstly, they are lightning quick, even by labrid standards, making them challenging to collect in the wild. And, in turn, this puts a constraint on the type of aquariums that are suitable for housing them, with large males of most species reaching 5-6 inches and needing ample room to stretch their fins. This would equate to, ideally, and aquarium that is at least 6 feet in length.

But the biggest reason that we dont hear more about Stethojulis is their poor reputation when it comes to long-term aquarium husbandry. The natural diet for many in this genus seems to be specialized on minute benthic organisms, things like tiny snails and forams and worms (truthfully, very little is actually known about what they are eating on the reef), and they can be hesitant to accept many aquarium foods. Combined with a highly active lifestyle and metabolism, this can make for a real husbandry challenge.

Stethojulis benefit from being added to a mature and large reef tank, one that is apt to have a variety of benthic invertebrates as potential snacking options. Its interesting to note that, unlike some similar wrasses (e.g. Anampses and Macropharyngodon), Stethojulis are not burrowers under normal circumstances. They will more often hide in rocks much in the way a Thalassoma wrasse or Bodianus hogfish might. This behavioral quirk is something common to the more primitive lineages in this family, and, sure enough, Stethojulis fits somewhere in the middle of this groups evolutionary history.

Of the ten species in the genus, we most often see Hawaiis endemic Stethojulis balteata, the Belted Wrasse, named for the bright orange band found in mature males. Females, on the other hand, are quite different in appearance, being mostly dark-colored, with a small yellow patch near the pectoral fins. These are rarely seen in aquarium exports given the limited demand for them, which in turn makes it nearly impossible to recreate that natural shoaling behavior of these fishes. Males arent the friendliest creatures to one another, so only add one to an aquarium.