How to Identify Atlantic Moonfish

To identify Atlantic Moonfish (Selene setapinnis), look at these key features.

Physical Characteristics

Body shape

compressed

Coloration

Overall silvery, highly reflective, often with a faint yellowish tint dorsally. Juveniles may have faint vertical bars that fade with age. No distinct spots or markings.

Scale type

cycloid

Mouth position

superior

Distinctive features

Extremely deep, compressed, and disc-shaped body, almost as deep as it is long., Steeply rising dorsal profile from the snout to the dorsal fin origin., Small, upturned mouth., Long, filamentous anterior rays in the dorsal and anal fins of juveniles, which shorten with age., Absence of scutes along the lateral line (a key differentiator from many other carangids).

Dorsal fin

Two dorsal fins; the first with 8 spines (often embedded in adults), the second with 1 spine and 21-24 soft rays. Anterior soft rays are elongated in juveniles.

Tail fin

Deeply forked caudal fin.

Pectoral fin

Long and falcate (sickle-shaped).

Distinctive fins

Anal fin with 2 detached spines followed by 1 spine and 18-21 soft rays. Anterior soft rays are elongated in juveniles, mirroring the dorsal fin.

Identification Tips

1. 1

   Body Shape

   Look for the extremely deep, compressed, and almost circular body profile. This is its most defining characteristic.

2. 2

   Mouth

   Observe the small, upturned mouth, which is characteristic of the genus Selene.

3. 3

   Lateral Line

   Note the absence of scutes (hard, bony plates) along the lateral line, which distinguishes it from many other jack species.

4. 4

   Juvenile Fins

   In juveniles, the elongated, filamentous anterior rays of the dorsal and anal fins are a clear identifier. These shorten significantly in adults.

5. 5

   Coloration

   The uniform silvery, highly reflective body without prominent markings is typical.

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