Bignose Unicornfish

Care

The Bignose Unicornfish is known from deep lagoons and seaward reefs, to depths of 50m (164ft). Here they may be found forming loose aggregations in the mid to upper reaches of steep drop offs, feeding on zooplankton and various marine plants and algae. Juvenile fish are mostly grey with a few bright blue spots distributed over the flanks and tail, along with blue lips. Adults are very imposing fish - they develop a convexly rounded, prominent snout (this being much less of a 'horn' than is seen in the majority of unicornfish), vertical blue lines that break up into small blue spots dorsally, in addition to a broad blue band extending from underneath the eye to the front of the rostral protuberance, and long flowing caudal streamers. Interestingly, these fish have the ability to show or hide their vivid blue markings, depending on mood. The Bignose Unicornfish is a very active, semi-aggressive acanthurid that requires a great deal of swimming space. Adults have been known to grow to almost two feet long, including the long flowing tail filaments. If you are blessed with a system of enormous proportions, the Bignose Unicornfish could make a wonderful centrepiece. The tank should contain plenty of live rock which this fish will enjoy grazing upon. Include plenty of hiding places that are large enough for the Bignose Unicornfish to retreat into quickly should it feel threatened, at the same time aiming for an aquascape that allows plenty of open swimming space along the front of the aquarium for such a powerful swimmer. Bignose Unicornfish are moderately aggressive towards tankmates, especially their own kind; for this reason it is best to house just one specimen per tank. There are good reports of this fish mixing with tangs of other genera; however it is recommended that the Bignose Unicornfish is the last addition to a set up, as it can be rather territorial to newcomers, especially similar fish species. It is best to source a medium sized specimen (i.e. over 4" in length) as they are more likely to acclimatise well to life in captivity. Conversely, extra large specimens may have a difficult time settling in, so aim for a healthy-looking fish that is neither too small nor excessively large. Avoid any specimens that appear "pinched" in the belly area, and do ask your retailer to show you that your chosen fish is feeding well prior to purchase. Bignose Unicornfish have a high metabolism and require small frequent feeds throughout the day. Powerful filtration/vigorous circulation and a high level of oxygenation are therefore essential for this energetic, voracious eater. Be sure to keep on top of water quality as this fish will not tolerate deteriorating water conditions. A large refugium with living rock can be most useful: macroalgae can be cultured on this rock and these pieces rotated with pieces from the main tank, so that the Bignose Unicornfish has a continual supply of natural foodstuffs to graze upon. Take care when handling Bignose Unicornfish, as their caudal spines (2 on each side of the caudal peduncle) are particularly large and can inflict very painful wounds. A period of quarantine can be a valuable procedure for the acclimatisation of all livestock, and it is of particular importance for the Bignose Unicornfish which can be fairly susceptible to developing marine whitespot. This can be difficult to treat in the reef aquarium. Ideally the fish should be quarantined and carefully observed in a separate aquarium for at least a fortnight before being introduced into your main display tank. May also be on sale as Scribbled Unicornfish, Vlamingii Tang, or Vlaming's Unicornfish.

Feeding

Offer a varied diet, consisting of mostly vegetable matter, in small amounts 3 times per day. In the wild, Bignose Unicornfish mainly consume various benthic algae and plants (including Cladophora spp. , Dictyota spp., Jania spp., Laurencia spp., Padina spp., and Turbinaria spp.) and planktonic meaty fare. Although this species will browse on some algae within the aquarium, it is of utmost importance to supplement the diet with a variety of foods including frozen herbivore rations, dried marine algae/Nori, green marine flake, Spirulina (blue-green algae), Spirulina-enriched brineshrimp, cucumber, lettuce etc. Include occasional feedings of Mysis shrimp and finely chopped krill. Adding a specially formulated vitamin supplement to any frozen foods will be beneficial to help prevent deficiencies which may lead to HLLE.

Breeding

This fish has not been bred in the home aquarium.