How to Identify Sacramento Blackfish

To identify Sacramento Blackfish (Orthodon microlepidotus), look at these key features.

Physical Characteristics

Body shape

compressed

Coloration

Adults are typically dark olive to black on the dorsal surface, fading to a lighter olive or grayish-white on the ventral side. Juveniles may be lighter and more silvery. Fins are usually dark.

Scale type

cycloid

Mouth position

superior

Distinctive features

Deep, compressed body, Small, upturned mouth, Large, prominent eyes, Small, embedded scales, Absence of barbels

Dorsal fin

Single dorsal fin, typically with 9-11 soft rays. Originates slightly anterior to the pelvic fin origin.

Tail fin

Moderately forked caudal fin.

Pectoral fin

Relatively small pectoral fins, positioned low on the body.

Distinctive fins

Pelvic fins are abdominal, located beneath the dorsal fin. Anal fin has 7-9 soft rays.

Identification Tips

1. 1

   Body Shape and Coloration

   Look for a deep, compressed body that is dark olive to black dorsally, fading to lighter ventrally. This dark coloration is a key identifier.

2. 2

   Mouth and Eyes

   Observe the small, distinctly upturned mouth, which is adapted for surface feeding and filter feeding. The eyes are relatively large and prominent.

3. 3

   Scales

   Note the small, almost embedded scales, which give the fish a smooth appearance despite being scaled.

4. 4

   Absence of Barbels

   Unlike some other cyprinids, the Sacramento Blackfish lacks barbels around its mouth.

5. 5

   Pharyngeal Teeth

   While not visible externally, their unique pharyngeal teeth (5-4 or 5-5, with a distinct grinding surface) are a definitive characteristic for ichthyologists.

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