How to Identify Common Bleak

To identify Common Bleak (Alburnus alburnus), look at these key features.

Physical Characteristics

Body shape

elongated

Coloration

Dorsal side is dark greenish-blue to olive-brown, flanks are brilliant silvery, and the belly is white. Fins are typically translucent or slightly yellowish, sometimes with a dusky margin.

Scale type

cycloid

Mouth position

superior

Distinctive features

Slender, laterally compressed body, Large, easily shed scales, Short lateral line that curves downwards anteriorly, Terminal, upturned mouth, Bright silvery flanks

Dorsal fin

Short, with 2-3 unbranched and 7-9 branched rays, originating behind the pelvic fin base.

Tail fin

Deeply forked, with pointed lobes.

Pectoral fin

Relatively long, reaching or nearly reaching the pelvic fin base, with 1 unbranched and 14-17 branched rays.

Distinctive fins

All fins are soft-rayed. The anal fin is long, with 3 unbranched and 15-20 branched rays.

Identification Tips

1. 1

   Body Shape and Coloration

   Look for a slender, silvery body with a dark back and white belly. The bright, reflective flanks are a key characteristic.

2. 2

   Mouth Position

   The upturned, terminal mouth is adapted for surface feeding and is a good indicator.

3. 3

   Lateral Line

   Observe the lateral line; it is incomplete or short and distinctly curves downwards anteriorly, often ending before the caudal peduncle.

4. 4

   Scales

   The scales are relatively large and easily detached, giving the fish a 'slippery' feel.

5. 5

   Fin Placement

   The dorsal fin originates behind the pelvic fin base, which helps distinguish it from some similar cyprinids.

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