Blackspot Piranha

Adult Blackspot Piranhas reach a length of 25–35 cm, with females typically being somewhat larger. Their bodies are massive, oval-shaped, and strongly compressed laterally. Outwardly, they are almost indistinguishable from a related species, the Red-bellied Piranha. Their coloration is characterized by a gray hue and silvery scales; under certain lighting, the fish can appear almost entirely white. The belly, lower part of the head, and anal fin are red. A distinctive feature is a dark spot located behind the operculum.

Originates from South America from the Orinoco River basin, covering large areas of Colombia and Venezuela.

Significant difficulties will arise when selecting tank mates for the Blackspot Piranha. If the piranhas are consistently well-fed, other fish may be relatively safe, provided they are comparable in size or significantly larger. Any small fish will inevitably be perceived as a food source. Intraspecific relationships are also complex: although they live in large groups in nature, this is primarily a defense mechanism against other predators. In the confined space of aquariums, where there is no external danger, it is not uncommon for a stronger individual to kill a weaker one. As a result, only one individual from the entire group may survive. It is advisable to keep a single fish, but with a very large tank, it might be possible to increase the number to 5–6 individuals or more.

For keeping a single Blackspot Piranha, aquariums with a volume of 400–500 liters are required. If a small shoal is planned, the volumes increase significantly, which is due to their behavioral characteristics, as will be discussed below. The aquarium decor for the Blackspot Piranha is not of fundamental importance; on the contrary, it is recommended to exclude certain decorative elements. For example, live plants will likely be eaten or uprooted from the substrate. Water quality is critically important. Since these fish produce a lot of waste, the filtration system is under significant load. High-performance external filters are essential here. In addition, it is necessary to replace a portion of the water weekly with fresh water, at least 30–50% of the total volume. In large aquariums, connecting to an automatic water change system is advisable. It is worth noting that piranhas go beyond typical amateur aquaristics, so this article does not cover all the intricacies of their keeping. Often, specialized companies or invited experts handle the maintenance of aquariums with these fish, leaving the owner to simply enjoy their “predatory” pets.

Although the piranha is often portrayed as a ferocious predator, its diet is actually quite diverse and includes not only live fish but also aquatic invertebrates, insects, as well as nuts, seeds, and fruits. In nature, they may pursue and eat weakened or dying fish. Contrary to legends spread by movies, piranhas do not attack animals and humans in the water; biting incidents are extremely rare. In a home aquarium, young fish can be fed bloodworms and small earthworms. Adult individuals readily accept pieces of fish meat and mussels, whole shrimp, and large earthworms.

As of the writing of this article, there have been no recorded cases of Blackspot Piranha breeding in home aquariums. In wild populations, two reproductive cycles are observed: one at the beginning of the rainy season, and another at the end of the year, in November or December. Spawning sites are dense thickets of aquatic plants.

This fish is distinguished by its hardiness and unpretentiousness. Health problems are most often associated with injuries, inadequate nutrition, or unsuitable water composition. When signs of illness appear, such as lethargy, changes in body shape, or loss of appetite, it is often enough to normalize the keeping conditions for the fish's body to cope with the ailment. However, in some cases, medication may be required. More detailed information on symptoms and treatment methods is available in the "Diseases of Aquarium Fish" section.

When choosing a Blackspot Piranha, preference should be given to individuals with active behavior that show curiosity about their surroundings. A healthy fish should have clean, tightly adhering scales without signs of damage, ulcers, or white film, as well as clear eyes without cloudiness. It is important to ensure there are no jaw or fin deformities, as any injuries in an aquarium environment can lead to secondary infections.

• avoid individuals that appear lethargic, constantly stay near the water surface, or, conversely, hide in the corners of the aquarium
• pay attention to the overall condition of the shoal: if there are many fish in the aquarium with damaged fins or bite marks, this may indicate excessive aggression, stress, or poor keeping conditions
• ask the seller about the fish's current diet, as a sudden change in accustomed food can provoke refusal to eat and weaken the immune system