How to Identify Blackback Butterflyfish

To identify Blackback Butterflyfish (Chaetodon melannotus), look at these key features.

Physical Characteristics

Body shape

compressed

Coloration

The body is predominantly white to pale yellow, transitioning to a darker yellow or orange on the posterior dorsal and caudal fins. A prominent, broad black band extends from the anterior dorsal fin, across the back, and down to the posterior part of the body, often forming a saddle-like marking. A distinct black bar runs vertically through the eye. The caudal fin is typically yellow with a clear or translucent margin. Juveniles may have a more pronounced ocellus (eyespot) on the dorsal fin, which fades with age.

Scale type

ctenoid

Mouth position

terminal

Distinctive features

Prominent black saddle-like band across the back, Black bar through the eye, Yellow caudal fin, Elongated snout

Dorsal fin

12-14 dorsal spines, 17-20 soft rays. The spiny portion is continuous with the soft-rayed portion.

Tail fin

Truncate to slightly emarginate.

Pectoral fin

Well-developed, typically clear to yellowish.

Distinctive fins

Anal fin with 3 spines and 15-17 soft rays. Pelvic fins are small and yellowish.

Identification Tips

1. 1

   Black Dorsal Saddle

   The most distinguishing feature is the broad, black band or saddle that covers the upper posterior part of the body, extending from the dorsal fin.

2. 2

   Eye Bar

   A vertical black bar passes through the eye, a common characteristic among many butterflyfish species, but distinct in its intensity and shape for C. melannotus.

3. 3

   Caudal Fin Color

   The caudal fin is typically bright yellow, providing a strong contrast to the body coloration.

4. 4

   Body Color

   The main body color is white to pale yellow, which helps to highlight the black markings.

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