Siganus insomnis is a new species of rabbitfish hailing from the Northern Indian Ocean around Sri Lanka, Southern India and Sri Lanka. While new species of rabbitfish don’t come along very often, the new “sleepless” rabbitfish is well worth the wait, supposedly being named Siganus insomnis due to their supposed nocturnal grazing behavior.
The sleepless rabbitfish Siganus insomnis is most closely related to S. lineatus, a species which is more prevalent throughout Indonesia and the Philippines and whose name has been used to refer to the new species as Siganus cf. lineatus by Kuiter and others. The new Siganus insomnis is distinguished by more thoroughly developed horizontal blue lines across the entire body, not just in the bottom half of the flanks as in S. lineatus.
In the Maldives the sleepless rabbitfish is found around coral atolls while around Sri Lanka and India juvenile and young Siganus insomnis are often found in brackish water habitats. The new species is described by David Woodland in the latest edition of ZooTaxa and while the description of the sleepless rabbitfish may be new, with ample imports of diverse fishes from Maldives and Sri Lanka it is highly likely that Siganus insomnis has already been made available to aquarists.
