Acanthicus adonis

Adult Acanthicus adonis typically reach a length of about 60 cm, but specimens growing up to a meter are sometimes encountered. A distinguishing feature of young fish is their bright spotted coloration. With age, this pattern gradually disappears, and the fish's body acquires a uniform gray hue. The first rays of the dorsal and pectoral fins transform into sharp spines, and the catfish's body itself is covered with numerous prickles. Their tail is large, with elongated filamentous tips.

Its origin is linked to South America, where it is found in the lower Tocantins River basin, located in the Brazilian state of Pará. It is possible that the natural distribution of this species is much wider and encompasses vast regions of the Amazon. Interestingly, similar fish are also exported from Peru. These catfish prefer river sections where the current is not too fast and there are plenty of hiding places.

Young specimens of this species are peaceful and get along well with other fish of comparable size. However, their behavior changes with age: the catfish become territorial and begin to show aggression towards any other inhabitants that enter their territory.

The optimal aquarium volume for a single catfish should be at least 1000–1500 liters. Various shelters are used for decorating such an aquarium, such as intertwined driftwood, rock formations creating caves and crevices, or decorative elements serving as refuges. Aquatic vegetation may only be appropriate for young fish, as adult Acanthicus adonis tend to dig up plants. Lighting should be subdued. To maintain high water quality within acceptable hydrochemical parameters and temperatures, a powerful filtration system and other specialized equipment are necessary. Regular partial water changes also imply the presence of separate systems for water preparation and drainage. Such aquariums are extremely bulky, their weight can reach several tons, and their maintenance requires significant financial investment, which puts them beyond the scope of amateur aquaristics.

This species is omnivorous and capable of consuming anything it can swallow. In natural conditions, they are often found near populated areas, where they feed on organic waste. In an aquarium environment, Acanthicus adonis readily accepts a variety of foods: these can be dry, live, and frozen foods, as well as pieces of vegetables and fruits.

Despite the scarcity of reliable information, successful cases of Acanthicus adonis breeding in artificial environments have been recorded. Spawning in these catfish occurs in underwater caves, with males taking responsibility for guarding the eggs. Females do not participate in the subsequent care of the offspring.

When kept in favorable conditions, fish rarely experience health deterioration. The occurrence of diseases usually indicates problems in keeping, such as polluted water, poor quality food, or injuries. In most cases, eliminating the root cause leads to recovery. However, sometimes medication may be required. Detailed information on symptoms and treatment methods can be found in the section "Diseases of aquarium fish."

When choosing, it should be noted that young specimens are often sold as ornamental fish that do not correspond to their enormous potential size. A healthy fish should show activity at night, have clean fins without signs of erosion, and have no visible body damage from sharp odontodes during transport. Avoid specimens with sunken bellies or signs of emaciation, as this may indicate problems with adapting to the aquarium diet.

• inspect the skin for white spots or ulcers
• check the integrity of the long filamentous processes on the fins
• assess the overall plumpness of the specimen, avoiding overly thin fish