How to Identify Redtail Surfperch

To identify Redtail Surfperch (Amphistichus rhodoterus), look at these key features.

Physical Characteristics

Body shape

compressed

Coloration

Silvery-white to brassy on the sides, often with 8-9 faint, vertical bars that may be indistinct. The most distinguishing feature is the bright red to reddish-orange coloration on the caudal (tail) fin, and often on the pelvic and anal fins. The dorsal fin may also have reddish hues. Some individuals may exhibit iridescent blue or green reflections.

Scale type

cycloid

Mouth position

terminal

Distinctive features

Bright red to reddish-orange caudal fin, Deep, compressed body, Small, terminal mouth, Large, cycloid scales

Dorsal fin

Single dorsal fin with 9-11 spines and 22-27 soft rays. The spinous portion is lower than the soft-rayed portion.

Tail fin

Moderately forked, bright red to reddish-orange.

Pectoral fin

Relatively large and rounded, clear to slightly yellowish.

Distinctive fins

Pelvic and anal fins often share the reddish coloration of the caudal fin. The anal fin has 3 spines and 27-32 soft rays.

Identification Tips

1. 1

   Caudal Fin Color

   The most reliable identifier is the bright red to reddish-orange coloration of the tail fin. This is usually very prominent.

2. 2

   Body Shape and Bars

   Look for a deep, compressed body with faint, often indistinct, vertical bars on the sides. The bars are typically 8-9 in number.

3. 3

   Mouth Size

   The mouth is relatively small and terminal, distinguishing it from some other surfperch species with larger or more inferior mouths.

4. 4

   Scale Size

   Possesses relatively large, cycloid scales, which are smooth to the touch.

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