How to Identify Diagonal-Banded Sweetlips

To identify Diagonal-Banded Sweetlips (Plectorhinchus lineatus), look at these key features.

Physical Characteristics

Body shape

compressed

Coloration

Adults: Body is white to light grey with numerous prominent, diagonal black or dark brown bands running from the dorsal fin towards the ventral side. The fins are typically yellow, often with black spots or stripes. The caudal fin is yellow with black spots. Juveniles: Strikingly different, with a black body and large, irregular white or yellow blotches and spots. As they mature, these blotches elongate and transform into the characteristic diagonal bands.

Scale type

ctenoid

Mouth position

terminal

Distinctive features

Thick, fleshy lips that become more prominent with age., Distinctive diagonal banding pattern in adults., Dramatic ontogenetic color change from juvenile to adult., Large, rounded caudal fin., Relatively small mouth compared to body size.

Dorsal fin

Single dorsal fin, deeply notched, with 12-14 spines and 16-20 soft rays. The spiny portion is longer than the soft-rayed portion.

Tail fin

Large, rounded to slightly emarginate caudal fin, typically yellow with black spots.

Pectoral fin

Moderately sized, rounded pectoral fins.

Distinctive fins

Anal fin with 3 spines and 7-8 soft rays. Pelvic fins are thoracic.

Identification Tips

1. 1

   Adult Coloration

   Look for the distinct diagonal black or dark brown bands on a white to light grey body, combined with yellow fins that often have black spots. The thick, fleshy lips are also a key indicator.

2. 2

   Juvenile Coloration

   Juveniles are entirely different, featuring a black body with large, irregular white or yellow blotches and spots. They often mimic toxic flatworms or nudibranchs to deter predators.

3. 3

   Body Shape

   Compressed, oval-shaped body with a relatively small mouth and prominent lips.

4. 4

   Behavior

   Adults are often seen resting in aggregations during the day, becoming more active at night. Juveniles may exhibit a 'rocking' or 'swaying' swimming motion.

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