The Very Longnose Butterflyfish (Forcipiger longirostris) - also known as the Big Longnose Butterflyfish - differs from the almost identical Longnose Butterflyfish (Forcipiger flavissimus) by having a longer snout and by the presence of speckles on the chest (visible just under the pectoral fin in the above picture). Both species are present in Niue.
I like that ... imagine the conversation "ooh, this one has a longer nose than the Longnose Butterflyfish ... what shall we call it?" ... "how about 'Very Longnose Butterflyfish'?" ... "but what if we find a new species with an even longer nose?" ... "we'll worry about that when the time comes!".