FishCommonVisible while snorkeling

Threadfin butterflyfish

Chaetodon auriga

A white-and-yellow body, herringbone lines and a long thread trailing from the dorsal fin – the threadfin butterflyfish is one of the reef's most elegant wanderers.

Photo: iNaturalist – (c) zsispeo, some rights reserved (CC BY-SA)

The threadfin butterflyfish (Chaetodon auriga) is pearl white at the front and glowing yellow at the rear, with two sets of dark lines crossing at right angles to draw a herringbone pattern on its flanks. A black bar covers the eye, and adults trail a long filament from the dorsal fin – the thread that gives the species its English name, while the scientific "auriga" means charioteer, the filament recalling his whip.

Among butterflyfish it is a remarkably versatile hunter: with its elongated snout it plucks worms, small crustaceans and coral polyps from crevices, samples the tentacles of sea anemones and even grazes algae. This flexible diet lets it thrive in many habitats, from lush coral gardens to rubbly lagoons. It patrols its territory in pairs or alone, and it behaves more boldly around divers than most of its relatives.

It is one of the most frequently seen butterflyfish around Hurghada: it turns up regularly in the lagoon of Dolphin House (Shaab El Erg), in the El Fanadir coral garden and on the Giftun plateaus, and it is easy to watch while snorkeling in the shallows. Curiously, the Red Sea population differs slightly from those elsewhere in the world – a detail given away by the eyespot.

Did you know?

Threadfin butterflyfish across the world's oceans wear a black eyespot on the dorsal fin – but the Red Sea population has dropped this marking. If you see a spotless one at Hurghada, that local peculiarity is exactly what is swimming in front of you.

Where can you meet it?

You will meet it on almost every dive and snorkel trip in the Dolphin House lagoon, the El Fanadir coral garden and on the Giftun plateaus.

Frequently asked questions

No, it is completely harmless – a peaceful, curious reef dweller that often lets divers approach closer than most butterflyfish. Move calmly and you can watch it from quite near.

Yes, it is one of the best snorkel fish: it forages regularly in shallow lagoons and on reef tops, even in water a metre deep. The white-and-yellow herringbone body is easy to recognise from the surface.

Its exact role is unproven, but researchers think it may help mislead predators: the trailing thread draws attention away from the fish's head. Only adults have it – juveniles still lack the filament.