Serrasalmus geryi

Serrasalmus geryi, known as the violet line piranha or Gery's piranha, is a species of piranha of the family Serrasalmidae. It is found in the lower Tocantins and Araguaia Rivers of Brazil. The species is notable for being the one of only the members of the genus Serrasalmus that can coexist with others of the same species in captivity, however caution is advised. Gery's Piranha reaches sizes up to 12 inches in length. As of 2018, it is classified as Least Concern by the International Union for Conservation of Nature.

Description
The body shape of Serrasalmus geryi is very laterally compressed, similar to other Serrasalmus genus members S. altuvei, S. hastatus, S. compressus and S. altispinis. The fish is distinctive at all ages, possessing a broad dark stripe running from the lower mouth to the top of the beginning of the dorsal fin. S. geryi does not exhibit sexual dimorphism.

The body is silver with numerous small spots on the flanks. The anal fin is hyaline with a broad black margin. The pectoral and ventral fins are clear. A humeral spot may be present. Eyes silvery to reddish-orange.

Mature individuals reach a length of 25 cm (10 inches), with specimens rarely longer than 20 cm (8 inches) in captivity.

== Care == Tank requirements:


 * Recommended tank sizes: 120x45x50 cm (48x18x20 in) for an adult specimen, minimum 60x30x30 cm (24x12x12 in) for a juvenile specimen, and minimum 150x50x60 cm (60x20x24 in) for multiple individuals.


 * Plants, driftwood or rocks provide hiding places; the tank lights should be dimmed.
 * Heavy filtration is required to deal with the large amounts of waste this fish produces.
 * A powerhead can be added to provide currents.
 * Fish can be dangerous to hands and other extremities. Care is required in handling.

Water temperature:


 * 24-29 degrees Celsius (76-84 degrees Fahrenheit).

Water chemistry:


 * pH should be between 6.0 - 8.0, ideal is slightly acidic to neutral water: pH 6.5 - 7.2. Soft water is preferred.

Compatible species:


 * S. geryi is one of the few Serrasalmus species that have successfully been kept in a group. However, it is highly recommended to keep Gery's Piranha as a solitary fish, as it remains a parasitic and highly aggressive species. If multiple individuals of this species are kept together, it should only be attempted by highly experienced piranha keepers who know exactly what they are doing, and know what risks are involved.

Breeding:


 * No instances of captive breeding have been reported yet.

Diet:


 * Fish (whole, fillet or feeders), shrimp, cockles, mussels, squid, insects, earthworms, pellets.
 * Food items such as poultry, mammal meat, and organ meat should be fed sparingly: once or twice a month at most. Meat needs to be unseasoned and trimmed of any fat.
 * On rare occasions, this species accepts vegetables, nuts, seeds, or fruit as well.


 * Live fish need to be quarantined first, so they are safe to feed (containing no diseases or parasites).
 * Goldfish, minnows and other members of the Cyprinid family (Carp-like fish) should be avoided, as these fish contain growth-inhibiting hormones (Thaiminase/Vitamin B1 inhibitors) that could negatively affect the piranha's health and development.