Care
The Big Longnose Butterflyfish is a generally uncommon deepwater species that inhabits seaward reefs amongst moderate currents, at depths between 60-200m (197-656ft). These fish are normally observed in pairs, feeding on tiny invertebrate life amongst the nooks and crannies with their extraordinary long snouts. The aquarium should be mature and should offer plenty of live rock for both grazing opportunities and sanctuary, as well as ample swimming space. There should be good filtration and areas of brisk water movement. The Big Longnose Butterflyfish should be kept singly as it will show much aggression towards its own kind and other butterflyfish species (the only exception to this rule is if a true mated pair can be obtained). It is best housed with other peaceful tankmates so that it does not feel intimidated when feeding. A dark brown colour morph from Hawaii is sometimes available, although they may not always retain the unusual colouration in captivity - many specimens apparently reverting to the normal yellow and, on occasion, back to brown again. A similar species, the Yellow Longnose Butterflyfish (F. flavissimus) is also often seen in the trade " this fish has a shorter snout, and a slightly larger mouth, than that of F. longirostris. The Yellow Longnose Butterflyfish also has a higher dorsal spine count (12-13) compared to the Big Longnose (10-11). Feeding may be a little challenging on account of the tiny mouth - do ensure all foodstuffs are small enough for the butterflyfish to consume. Aquarists often have the greatest success in keeping this fish in tip-top condition when an ongoing supply of tiny amphipods and copepods are cultured in an attached fishless refugium - the butterflyfish will devour these with much enthusiasm. The Big Longnose Butterflyfish makes for a wonderful addition to the mature reef aquarium, but your success with this species very much depends on the provision of a suitably spacious, current-swept rocky reef with friendly companions, in addition to ample and varied feedings.
Feeding
Offer a wide variety of foods, fed in small amounts several times per day. Frozen foods such as Mysis shrimp, vitamin-enriched brineshrimp, finely chopped clam/mussel/cockle/ crab/shrimp/squid etc should be given. Ensure the larger foodstuffs are chopped into small enough pieces on account of butterflyfish having tiny mouths. An attached fishless refugium could be used to culture an ongoing supply of small amphipods and copepods.
Breeding
The Big Longnose Butterflyfish has not been bred in the home aquarium. In the wild, this species forms distinct pairs and buoyant eggs are scattered in the open water, becoming part of the plankton. The young pass through a lengthy planktonic stage as tholichthys larvae where the body is covered in large bony plates extending from the head. They lose these bony plates as they mature.
