Phalacronotus

Adults of this fish can reach a length of 60–70 cm. Its body is elongated, noticeably compressed laterally, resembling the shape of a knife blade. An interesting feature is the absence of a dorsal fin, as well as a long anal fin that extends almost from the head to the very tail, complementing its appearance. The body coloration is usually grayish-silver. Speckles or thin stripes can be seen on its body, the presence of which depends on the specific region from which the fish originates.

The origin of this fish is associated with Southeast Asia, where its natural habitat covers vast territories: from the northern provinces of Thailand through Laos, Cambodia, Vietnam and Peninsular Malaysia, as well as the Greater Sunda Islands of Sumatra, Borneo and Java. Phalacronotus is found in all major river systems of the region, inhabiting main channels and large tributaries, and also penetrating into flooded areas of the tropical forest during the rainy season.

Despite its predatory nature, this fish is surprisingly peaceful. It coexists well with both its own kind and other species, the main condition being that they are large enough not to be perceived as prey. However, it should be remembered that any small fish will inevitably become a target for hunting.

Such a large fish naturally requires an aquarium of appropriate size. A volume of at least 1500 liters is recommended for a single specimen. The choice of decor is not critical; it is sufficient to provide subdued lighting and leave enough open swimming space. Keeping Phalacronotus involves certain difficulties. The most laborious and expensive task is maintaining stable water conditions within an acceptable range of temperatures and hydrochemical values. A tank weighing more than one ton, as well as all water purification systems, imply solving serious engineering problems, which puts such a project beyond the scope of ordinary amateur aquaristics.

This fish can be classified as a predator that hunts primarily in the water column or near the surface. Catfish caught in the wild often refuse alternative products and require live fish for feeding. At the same time, individuals raised in captivity on commercial fish farms have successfully adapted to a diet of fresh or frozen meat products. They must not be fed mammalian or avian meat: the lipids it contains cannot be properly metabolised by the fish and lead to excess fat deposits and even organ degeneration.

At the time of writing, breeding of this catfish species in aquarium conditions has not been recorded. The main source for commercial trade is fish farms, where reproduction is stimulated using hormonal preparations.

Most health problems in fish often arise from unsuitable keeping conditions. Maintaining a stable and comfortable habitat is a key factor for successful keeping. If symptoms of illness appear, the first step is to check the water quality. If deviations are found, it is important to take immediate measures to eliminate them. If the symptoms do not disappear or worsen, medicinal treatment may be required.

When purchasing Phalacronotus, it should be noted that it is a large predator requiring significant space, so acquisition is only permissible if a prepared aquarium of 500–1000 liters or more is available. Young specimens are often sold without proper information about their future size, which can reach 70 cm. When choosing, it is important to assess the condition of the fish in the store: — absence of skin damage, ulcers, film, or spots on the body; — clean and intact fins without signs of erosion or torn edges; — clear, not cloudy eyes without signs of inflammation; — calm but confident behavior, absence of signs of panic or apathy. It is recommended to clarify the type of diet with the seller, as wild specimens may refuse non-live food, preferring live fish. Avoid purchasing specimens that appear emaciated or show signs of stress, such as constant chaotic movement or attempts to jump out of the aquarium. Given the predatory nature of the species, do not purchase the fish if your aquarium contains small tankmates that could become prey. It is also worth ensuring there are no signs of disease in other inhabitants of the communal aquarium in the store, as this species is sensitive to water quality and parameter instability in a new environment.