Blacktail butterflyfish
A coral-grazing butterflyfish native to the Red Sea.
The blacktail butterflyfish (Chaetodon austriacus), also called the black-tailed or exquisite butterflyfish, is a marine ray-finned fish in the family Chaetodontidae. It naturally lives in the western Indian Ocean, but has also entered the Mediterranean Sea via the Suez Canal as a Lessepsian migrant.
Its native range covers the Red Sea and southern Oman. One individual was recorded near Tel Aviv, Israel, in 2011, likely having traveled from the Red Sea.
Taxonomically, this species belongs to the subgenus *Corallochaetodon*, along with the melon butterflyfish (*C. trifasciatus*), the oval butterflyfish (*C. lunulatus*), and probably the Arabian butterflyfish (*C. melapterus*). These are thought to be closely related to the subgenus *Citharoedus* (a name that is a junior homonym of a mollusk genus), which includes the scrawled butterflyfish (*C. meyeri*). If the genus *Chaetodon* is split, both groups might be placed in the genus *Megaprotodon*.
The blacktail butterflyfish grows up to 14 cm long. It is orange with thin, curved black stripes, and its anal fin and tail are black. Juveniles have a whiter upper body and white bands on the tail. The similar melon and oval butterflyfish have less black on their caudal and anal fins.
These fish prefer coral-rich areas at depths of 0.5 to 20 meters, such as seaward reefs, lagoons, or bays. Adults usually travel in pairs, defending a territory, while juveniles hide among coral branches. They feed on coral polyps and sea anemone tentacles.
- Scientific name
- Chaetodon austriacus
- Maximum length
- 14 cm
- Depth range
- 0.5 to 20 m
- Native range
- Red Sea and southern Oman
- Family
- Chaetodontidae
- Subgenus
- Corallochaetodon
Lore & Background
The blacktail butterflyfish is up to 14 cm long and is orange with thin, curved black stripes. Its anal fin and tail are black. The body of juveniles is whiter above with white bands on the tail. The melon butterflyfish (C. trifasciatus) and the oval butterflyfish (C. lunulatus) are similar in coloration but have less black on the caudal and anal fins.
Together with the melon and oval butterflyfishes and probably also the somewhat aberrant Arabian butterflyfish (C. melapterus), the blacktail butterflyfish makes up the subgenus Corallochaetodon. They are probably quite close to the subgenus called Citharoedus, which contains for example the scrawled butterflyfish (C. meyeri). Like that group, they might be separated in Megaprotodon if the genus Chaetodon is split up.
Black-tailed butterflyfishes tend to be found in coral-rich areas between 0.5 and 20 m deep, on seaward reefs or in lagoons or bays. Adults are generally found in pairs patrolling a territory or range while juveniles are found among coral branches. This species grazes on coral polyps and sea anemone tentacles.
Reader's Guide
The blacktail butterflyfish is notable as a Lessepsian migrant, having reached the Mediterranean Sea through the Suez Canal, with a single record reported in 2011 in the vicinity of Tel Aviv (Israel), a likely migrant from the Red Sea. Its native distribution is limited to the Red Sea and southern Oman. Ecologically, it is a coral specialist, grazing on coral polyps and sea anemone tentacles, and is typically found in coral-rich areas between 0.5 and 20 m deep on seaward reefs or in lagoons or bays. Adults patrol territories in pairs, while juveniles shelter among coral branches. Taxonomically, it belongs to the subgenus Corallochaetodon along with the melon and oval butterflyfishes, and possibly the Arabian butterflyfish. This group is closely related to the subgenus Citharoedus, which includes the scrawled butterflyfish, and may be reclassified into the genus Megaprotodon if Chaetodon is split. The species reaches up to 14 cm in length and is distinguished by its orange body with thin black stripes and black anal and tail fins, with juveniles showing whiter bodies and white tail bands.
Did You Know?
- The blacktail butterflyfish is also known as the black-tailed butterflyfish or exquisite butterflyfish.
- It has reached the Mediterranean Sea as a Lessepsian migrant through the Suez Canal.
Frequently Asked Questions
What is the Blacktail butterflyfish?
The Blacktail butterflyfish (Chaetodon austriacus) is a small marine ray-finned fish in the family Chaetodontidae, also known as the black-tailed or exquisite butterflyfish. It is classified within the subgenus Corallochaetodon alongside a few close relatives.
Where is the Blacktail butterflyfish native to?
Its natural range is limited to the western Indian Ocean, specifically the Red Sea and the waters off southern Oman. It inhabits shallow reef environments, typically between 0.5 and 20 meters in depth.
How big does the Blacktail butterflyfish get?
This species tops out at roughly 14 centimeters in total length, making it a modestly sized member of the butterflyfish family.
What does the Blacktail butterflyfish eat?
It is a coral-grazing specialist, feeding primarily on coral polyps. This dietary niche ties the species closely to living coral reef habitats in its native range.
How did the Blacktail butterflyfish reach the Mediterranean Sea?
It has entered the Mediterranean as a Lessepsian migrant, moving through the Suez Canal from the Red Sea. A single specimen was recorded near Tel Aviv, Israel, in 2011, confirming its arrival in these new waters.
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