How to Identify Blue and Yellow Fusilier

To identify Blue and Yellow Fusilier (Caesio teres), look at these key features.

Physical Characteristics

Body shape

torpedo

Coloration

The anterior two-thirds of the body is brilliant blue, transitioning abruptly to a bright yellow on the posterior third, including the caudal peduncle and caudal fin. The dorsal fin is typically blue with a yellow margin, and the pectoral fins are often yellowish. Juveniles may exhibit a more uniform blue coloration with less pronounced yellow.

Scale type

ctenoid

Mouth position

terminal

Distinctive features

Abrupt bicolored pattern (blue anterior, yellow posterior), Deeply forked caudal fin, Small, protractile mouth, Elongated, fusiform body

Dorsal fin

X-XI spines, 14-16 soft rays; continuous with a slight notch.

Tail fin

Deeply forked, bright yellow.

Pectoral fin

19-22 rays; relatively long and pointed.

Distinctive fins

Pelvic fins are small and located abdominally. Anal fin has III spines and 11-13 soft rays.

Identification Tips

1. 1

   Coloration

   The most distinguishing feature is the sharp demarcation between the blue anterior body and the yellow posterior body and caudal fin. This pattern is consistent in adults.

2. 2

   Body Shape

   Its elongated, torpedo-shaped body is characteristic of fusiliers, adapted for fast swimming in open water.

3. 3

   Schooling Behavior

   Always observed in large, active schools, often numbering in the hundreds or thousands, making them easily identifiable in their natural habitat.

4. 4

   Mouth

   The small, highly protractile mouth is indicative of its planktivorous diet, used for sifting small organisms from the water column.

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