Serrasalmus spilopleura

A Little More Information...

Serrasalmus spilopleura, also known as Ruby Red, is a South American piranha sought after for its warm coloration and robust body shape. Associated with the Rio Araguaia in Brazil, it inhabits freshwater environments where shoreline vegetation provides cover and ambush areas. Its opportunistic predatory behavior requires a spacious, carefully maintained aquarium with strong filtration. This form is offered as a wild-collected specimen and as a Ton.Fish exclusive in Canada. With a rarity rating of Very rare, it is best suited to experienced aquarists able to meet its specific requirements.

General species description

Serrasalmus spilopleura is a predatory characiform from the family Characidae, subfamily Serrasalminae. It has the typical piranha body plan: a laterally compressed body, well-developed fins and dentition adapted for cutting. The species is more colorful than several commonly kept piranhas, with reddish or copper tones that become especially visible in adults. It is generally cautious when introduced to a new environment, becoming more confident once the aquarium is stable. Care requires clean water, consistent oxygenation and careful handling, since the teeth are sharp and the fish may react quickly when stressed.

Geographic origin and biotope

This population comes from Brazil, in the basin of the Rio Araguaia. Its habitat includes river sections, side channels and shoreline areas influenced by seasonal water-level changes. Current strength may be moderate in backwaters and stronger in main channels. The bottom is generally made up of sand, gravel and plant debris, while the banks contain roots, submerged branches and dense vegetation. In the aquarium, soft to slightly acidic, warm and well-circulated water is preferable to a bare layout or very bright lighting.

Precise location and local name

The reference locality supplied for this strain is the Rio Araguaia in Brazil. In Brazilian local usage, the name piranha-amarela is associated with yellowish or golden piranha forms, while piranha is the general vernacular term. The trade name Ruby Red emphasizes the red highlights seen in some individuals. Because this is a wild fish that is very rare in the aquarium trade, its geographic origin should be clearly retained when the fish is sold or maintained.

Appearance and physical characteristics

Serrasalmus spilopleura has a deep, compact and laterally compressed body, with a strong head and jaws equipped with triangular teeth. Adults usually show a silver or golden base color enhanced by ruby-red highlights, especially on the fins and lower body. The dorsal and anal fins contribute to its balanced profile, while the caudal fin provides strong acceleration. Coloration varies with age, health, lighting and social conditions. A dark background, high water quality and a varied diet help bring out the copper and red tones.

General diet

Serrasalmus spilopleura is an opportunistic predator with a mainly carnivorous diet. In aquaria, feeding should consist of suitable portions of fish intended for aquarium use, shrimp, mussels and other appropriate marine or freshwater foods. Frozen foods are convenient and help provide variety. Avoid feeder fish from uncertain sources, mammal meat and excessive feeding, which can unbalance the diet and quickly degrade water quality. The important rule is to feed moderately, remove uneaten food and monitor body condition instead of encouraging overly rapid growth.

Essential data

• Origin river: Rio Araguaia
• Local name used: Piranha-amarela
• Origin of the scientific name: A genus name and specific epithet derived from Greek and Latin roots
• Etymology of the full name: Serrasalmus means “saw-toothed salmon” or refers to saw-like dentition; spilopleura means “spotted flank,” from spilos, spot, and pleura, side
• Common/vernacular names: Ruby Red, piranha, piranha-amarela
• Family: Characidae
• Subfamily: Serrasalminae
• Name pronunciation: seh-rah-SAL-moos - spih-loh-PLOOR-ah
• Discovery: Rudolf Kner, 1858
• Maximum adult size: About 30 cm
• Water temperature and pH: 24 to 30 °C; pH 6.0 to 7.5
• Waterway appearance and surrounding vegetation: Rivers and side channels with wooded banks, roots, submerged branches and shoreline vegetation
• Typical tankmates: Comparable-sized characins, robust cichlids, armored catfish and other large fish from the basin
• Temperament and behavior: Opportunistic predator, generally cautious, capable of quick reactions and defensive bites
• Water depth: Variable; mainly shorelines, backwaters and shallow to intermediate channels
• Sexual dimorphism: Limited; external differences are difficult to use reliably
• Bottom structure and flow: Sand, gravel and plant debris; flow varies from moderate to strong depending on the area

In your aquarium

Success depends on a long, spacious aquarium, a securely fitted lid and filtration capable of handling a heavy organic load. Maintain stable water at 24–30 °C, with good oxygenation and regular water changes. A layout using roots, branches and open swimming areas helps reduce stress without taking away too much swimming space. Always handle this fish with great care. Since it is a wild, very rare fish and a Ton.Fish exclusive in Canada, its purchase should be carefully planned around its carnivorous diet, adult size and predatory behavior.