Description:

The Chevroned Butterflyfish (Chaetodon trifascialis), also known by names like the Triangulate Butterflyfish or V-lined Butterflyfish, is a striking and beautiful fish with a significant drawback for most home aquarists: its highly specialised diet.

General Characteristics

Size: They can grow up to 18 cm (7.1 inches) in total length.

Appearance: This butterflyfish has a white or pale body covered in a pattern of black, chevron-shaped markings. It has a distinctive black bar running through its eye and a black caudal (tail) fin with a yellow margin.

Habitat: The Chevroned Butterflyfish is widely distributed throughout the Indo-Pacific region, from the Red Sea and East Africa to the Hawaiian and Society islands. It is a territorial fish that inhabits shallow, protected seaward reefs and lagoons, where it is closely associated with Acropora corals.

Diet: The Primary Challenge
This is the most critical factor for anyone considering this fish for an aquarium. The Chevroned Butterflyfish is an obligate corallivore, meaning it feeds almost exclusively on the polyps and mucus of Acropora corals, particularly Acropora hyacinthus.

Specialized Feeder: Unlike some other butterflyfish that can be weaned onto other foods, this species is extremely difficult, and often impossible, to transition to a captive diet.

Reef-Safe? Absolutely Not: Due to its specialized diet, this fish will relentlessly pick at and consume the polyps of stony corals in a reef tank, particularly Acropora species. It is not considered “reef-safe” by any means.

High Mortality: Because of their specialized feeding requirements, a very high percentage of these fish die shortly after being collected and placed in a home aquarium. Unless an aquarist can provide a continuous and sufficient supply of live Acropora coral, the fish will likely starve.

Aquarium Care (for dedicated, experienced aquarists)
Given the severe dietary challenges, this fish is only suitable for a select few with the resources and expertise to meet its needs.

Tank Size: A very large tank is required, with a minimum of 200 gallons (750 liters) often cited, to provide ample swimming room and a large volume for stable water parameters. A larger tank also increases the potential for a sustainable source of food if it is a dedicated coral-farmed system.

Water Parameters: Standard, high-quality marine water parameters are necessary.

Temperature: 75-82F (24-28C)

pH: 8.1-8.4

Specific Gravity: 1.020-1.025

Aquascaping: The tank should be set up to mimic a natural reef, with an abundance of live rock providing hiding places.

Temperament: The Chevroned Butterflyfish is a territorial species. It will defend its territory from other coral-eating butterflyfish and other members of its own species. It is best kept as a single specimen or a verified mated pair.

Conservation Status: This species is listed as “Near Threatened” by the IUCN, largely due to its dependency on Acropora corals, which are highly susceptible to coral bleaching events and other habitat loss. This further reinforces the ethical concerns of keeping this species in captivity.

In summary, while the Chevroned Butterflyfish is visually stunning, its specific and demanding dietary needs make it a very poor choice for almost all home aquariums. It is a fish that is best left in the wild, where its unique feeding behaviour plays a critical role in the health of coral reefs.