How to Identify Redeye Piranha

To identify Redeye Piranha (Serrasalmus rhombeus), look at these key features.

Physical Characteristics

Body shape

compressed

Coloration

Highly variable. Juveniles are often silvery with dark spots. Adults can range from silvery-grey to dark grey, almost black, with a metallic sheen. The operculum (gill cover) often has a reddish or orange tint. Eyes are typically red, especially in adults, giving rise to the common name. Some populations exhibit a more uniform dark coloration, while others retain some spotting.

Scale type

cycloid

Mouth position

terminal

Distinctive features

Robust, deep, and laterally compressed body., Large, powerful jaws with sharp, interlocking, triangular teeth., Prominent red eyes (though intensity varies)., Adipose fin present., Strongly keeled belly with serrations (hence 'Serrasalmus').

Dorsal fin

Single, relatively short-based dorsal fin, positioned mid-body.

Tail fin

Caudal fin is typically emarginate to slightly forked, often with a dark band at the base.

Pectoral fin

Pectoral fins are relatively small.

Distinctive fins

Anal fin is long-based, extending from behind the anus to the caudal peduncle. Adipose fin is small and fleshy.

Identification Tips

1. 1

   Body Shape

   Look for a deep, rhomboid (diamond-shaped) body that is strongly compressed laterally.

2. 2

   Eye Color

   The prominent red coloration of the eyes is a key identifier, though it can vary in intensity.

3. 3

   Teeth

   Observe the characteristic sharp, triangular, interlocking teeth in the powerful jaws (caution advised).

4. 4

   Coloration

   Adults are typically silvery-grey to dark grey/black, often with a metallic sheen. Juveniles may have more pronounced spotting.

5. 5

   Serrations

   Feel for the serrated keel along the belly, a defining feature of the genus Serrasalmus.

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