Small-toothed Whiptail

Pentapodus caninus

A fish of the Nemipteridae family. The juvenile displays bluish body with two lengthwise yellow bands, with the upper thinner than the lower. Colorless as an adult.
Pentapodus caninus - Small-toothed Whiptail It was also displaying some dark blotches as it was preparing for the night and many fishes change to darker coloration during night time.   
Another example you can see is in Diverosa web site:
https://www.diverosa.com/categories/fishes, Coral breams/L/IMIb-234_Pentapodus_caninus_Big-tailed_besugo_night_coloration.jpg      Fall,Geotagged,Malaysia,Pentapodus caninus,Small-toothed Whiptail

Appearance

Size: 14 inches - 35 cm
Dorsal spines (total): 10; Dorsal soft rays (total): 9; Anal spines: 3; Anal soft rays: 7. Head scales reaching forward to or just in front of level of anterior nostrils. Scaled area between nostrils with a distinct naked medial wedge-shaped notch. Suborbital scaly posteriorly. Lower limb of preopercle with 2 or 3 scale rows. Pelvic fins moderately long, reaching to or almost to level of anus. Upper lobe of caudal fin slightly longer than lower. Axillary scale present. Color: Upper body pale blue, lower whitish.

Distribution

Indo-West Pacific Ocean: South China Sea to the Gilbert Islands, north to Southern Japan, and south to New Caledonia.

Status

Least Concern.

Habitat

Inhabits sandy bottom areas on coral reefs and usually found at depths between 6 - 100 feet (2 - 30 m) where it feeds upon small fishes and benthic invertebrates.

Food

Fish flesh, shrimp, clams, mysis, scallops, worms.

References:

Some text fragments are auto parsed from Wikipedia.

http://www.saltcorner.com/AquariumLibrary/browsespecies.php?CritterID=1634
http://fishbase.sinica.edu.tw/Summary/SpeciesSummary.php?ID=5867&AT=Kitsun-un
Taxonomy
KingdomAnimalia
DivisionChordata
ClassActinopterygii
OrderPerciformes
FamilyNemipteridae
GenusPentapodus
SpeciesPentapodus caninus
Photographed in
Malaysia