Serrasalmus gouldingi

Serrasalmus: from the Latin serra, meaning 'saw', and salmo, meaning 'salmon', the former in reference to the serrated ventral keel in genus members, and the latter to the original placement of the type species in the genus Salmo.

gouldingi: named in honour of ecologist Michael Goulding, for his “indefatigable efforts in collecting Amazonian fishes and understanding the ecosystem in which they live, helping the senior author in the field, and for sharing his first-hand knowledge of Amazonian piranhas".

This species is widely distributed within the rio Negro drainage in northern Brazil, from above its confluence with the Casiquiare watershed at least as far south as the Archipelago das Anavilhanas in the lower Negro basin, and possibly to its mouth. It also occurs throughout the Casiquiare system, and possibly the upper Orinoco, but there appear to be no confirmed records from the latter.

Type locality is 'Anavilhanas, Río Negro, Brazil, 2°50'S, 61°00'W'.

This species' native rivers contain acidic, mineral-poor blackwater environments with brownish, tannin-stained water.

An aquarium measuring at least 150 ∗ 60 ∗ 60 cm60 ∗ 24 ∗ 24 in is required to house a single specimen.

Choice of décor is not as critical as water quality and the amount of open swimming-space provided. Serrasalmids can behave skittishly when maintained in completely bare set-ups, however, therefore it is recommended to provide a degree of cover in the form of driftwood and/or surface vegetation.

Serrasalmus spp. typically produce a lot of waste so the use of one or more over-sized external filters is essential. If possible buy units with built-in heaterstats or at least fit a sturdy heater-guard since adults are capable of damaging submerged equipment. Sump systems also work well, and the heaterstat can be housed within.

Aim to change 30-50% of the aquarium volume each week and exercise extreme care when performing such maintenance or when netting the fish for any reason.

Serrasalmus species tend to be somewhat opportunistic feeders in the wild, although they display a preference for small fishes, chunks of fish flesh, and fish fins.

In the aquarium small individuals can be offered chironomid larvae (bloodworm), small earthworms, chopped shellfish and suchlike, while adults will accept strips of fish flesh, live river shrimp, larger earthworms, etc.

This species should not be fed mammalian or avian meat such as beef heart or chicken since some of the lipids contained in these cannot be properly metabolised by the fish and can cause excessive fat deposition and even organ degeneration. Similarly, there is no benefit in the use of 'feeder' fish such as livebearers or small goldfish which carry the risk of parasite or disease introduction, and tend not have a high nutritional value unless properly conditioned beforehand.

Best maintained alone as a single specimen.

Unrecorded.

Unrecorded.

This species occasionally appears in the ornamental trade where it is sometimes referred to as 'blue tiger piranha'

Following Fink and Machado-Allison (1992)[1], it can be distinguished from other members of the genus by the following combination of characters: body shape deep and rhomboid; head robust, snout blunt; eye large; mouth moderate, jaw projecting; 1-3 ontogeneticlly variable ectopterygoid teeth; 2 unbranched and 14-16 branched dorsal-fin rays; first pterygiophore level with the fifth vertebral neural process; pre-anal spine present; 37-38, usually 38, vertebrae; body scales small and numerous; 93-97, usually 95, lateral line scales; 24-25 pre-pelvic serrae, 8-10 post-pelvic serrae; 23-27, usually 25, short, wide-based gill rakers.

Some components of the colour pattern are also useful for identification, including: eye bluish or coppery; vertically-elongate dark spots on the body; caudal-fin with a basal blackish band; humeral spot absent.

The family Serrasalmidae contains 16 genera comprising the piranhas, pacus and relatives. Their characteristic features include a compressed body shape, long dorsal fin with 16 or more rays, and a variable number of sharp serrae formed by modified abdominal scales on the ventral surface. They are found in numerous habitat-types from lowland floodplains and flooded forests to upstream headwaters, and occur in all major South American river systems east of the Andes. Some species perform unique ecological functions such as seed dispersal, or sustain important inland fisheries and aquaculture projects.

Members display three main feeding habits: carnivory (flesh-eating), frugivory (fruit and seed-eating) and lepidophagy (eating the scales and fins of other fishes). Carnivorous species normally possess a single row of tricuspid teeth on each jaw, frugivores tend to have two series of incisor or molariform teeth on the premaxilla, one row of teeth on the dentaries and often a pair of symphyseal teeth, while in lepidophages the teeth are tuberculate and located on the outer edge of the premaxilla.

The evolutionary history of serrasalmids has been studied by various authors, with the most recent analyses (Thompson et al., 2014)[7] supporting the existence of three major clades within the family. The "pacu" clade contains the genera Colossoma, Mylossoma and Piaractus, the "true piranha" clade includes Metynnis, Pygopristis, Pygocentrus, Pristobrycon, Catoprion, and Serrasalmus, and the Myleus clade comprises the Myleus-like pacus.