A deep-living butterflyfish with a dark diagonal bar, normally below 30 metres and rarely reached on a recreational dive.
To about 15 cm. Yellow with a prominent black scythe-shaped mark on the side, a blackish diagonal band from the snout to the start of the dorsal fin, black on the spiny dorsal and on the bases of the soft dorsal and anal fins, and a grey tail with narrow black borders.
The southern scythe butterflyfish was split off from it and is the species to separate it from where they meet: the snout band is black here and grey there, and the dorsal fin base yellow here and greyish there.
Three to over two hundred metres by one source and ten to a hundred and fifty by another, on rocky boulder-strewn deeper reef. Alone or in small groups, pairing to breed, taking urchin tube feet, crustaceans, worms and small invertebrates.
Two notes on the name. Following the split, STRI now calls this the northern scythe butterflyfish and restricts it from southern California through the Gulf of California to the Revillagigedos. FishBase’s range, running to Peru and the Galapagos, predates the split. The Revillagigedo record here stands under either treatment. It is seldom collected, because of the depth.
Ratings are per location: 1 means found on most dives that look for it, 5 means a handful of records. Where enough dives have been logged the figure is calculated from them; otherwise it is an editorial estimate, and says so. We publish habitat and destination, not the dive site.