Orange-nosed butterfly, Chaetodon flavirostris


Matt Clarke checks out a butterfly that should only be attempted by the most experienced marine aquarists.

Common names: Orange-nosed butterfly, Black butterfly and Dusky butterfly.
Scientific name: Chaetodon flavirostris, Gunther, 1874
Origin: South-western Pacific Ocean between Eastern Australia and Pitcairn Islands.
Size: Up to 20cm/8”.
Diet: Wild fish are believed to be omnivorous and feed mainly on coral polyps, benthic invertebrates and algae. However, they are considered exceptionally difficult to feed in captivity.

Aquarium: This reef-associated butterfly should not be attempted unless you have a successful track record with hard-to-feed, largely corallivorous butterflies. Sometimes it’s possible to persuade the more difficult Chaetodon to feed when juvenile, but larger fish tend to be more difficult.

Always check these fish are feeding properly and putting on weight prior to purchase.

Like other butterflies, this species needs spacious quarters. A fish-only system with live rock, or fast-growing corals you don’t mind the butterfly consuming, would be the best choice. Tank size should be at least 150cm/5’, ideally larger.

In the wild juveniles tend to be solitary, but most older fish are seen in pairs.

Notes: Like other butterflies, this species changes appearance as it ages and juveniles are arguably prettier than adults. They have a white face, operculum and shoulder with a dark stripe running through the eye and a dark spot on the rear of the dorsal fin.

As they get older, the snout turns white with a yellow band, colours darken and they develop a black lump on the forehead.

Availability: These are seen occasionally but difficult to get feeding, so most non-specialist retailers avoid stocking them. They’re best avoided unless you’re a butterflyfish expert.
Price: On sale at The Abyss, Stockport, for £90.

This item first appeared in the April 2010 issue of Practical Fishkeeping magazine. It may not be reproduced without written permission.