Two-spot Mystus

Adults grow to approximately 6 cm in length. Their bodies have a pinkish hue, and their fins are transparent. Two dark marks stand out on the body: one spot is located immediately behind the head, and the other is a stripe at the base of the tail. Sexual dimorphism is quite weak, making it difficult to distinguish males from females.

The natural habitat of this species is on Sumatra Island in Indonesia, which is part of the vast Southeast Asian region. Here, the catfish inhabits characteristic peat swamps, where the water is very soft, acidic, and takes on a rich brown color due to the high content of organic matter. Unfortunately, Mystus bimaculatus is currently endangered, which is due to intensive human economic activity on the island.

This species is distinguished by its peaceful and friendly nature, maintaining it even towards smaller fish. It coexists perfectly with other representatives of its natural environment, such as Rasbora, Glass Catfish, and Gourami. The Mystus can be kept either alone or in a group of conspecifics, as intraspecific conflicts are not observed.

For a single catfish, a tank volume of at least 40 L is optimal. In the aquarium setup, it is recommended to provide dense thickets of rooted plants and various snags. Dim lighting is desirable; several clusters of floating vegetation will help create additional shade. Regarding water conditions, it is advisable to approximate natural ones: this means not only achieving similar pH and dGH values but also using materials that will enrich the water with tannins, giving it a characteristic "tea" tint. Natural bogwood, as well as dried oak leaves or Indian almond leaves and bark, are suitable for this. However, it should be noted that the catfish can adapt to other living conditions.

Regarding diet, the catfish is completely undemanding. In a home aquarium, it readily accepts all common types of food — be it live, frozen, or dry. An important condition is that the food must be sinking, as the Two-spot Mystus finds it inconvenient to feed from the water surface.

Breeding this catfish in captivity is possible, but commercial breeders resort to hormonal injections. For successful natural breeding, it is necessary to create conditions as close to natural as possible. The Two-spot Mystus spawns in a species-specific aquarium with acidic water (pH in the range of 4.0–5.0) and zero hardness, using peat substrate. As soon as the females are gravid with eggs, a daily procedure of partial water changes with fresh water, identical in hydrochemical composition but with a lower temperature, is initiated to stimulate spawning. Any attempts to breed these catfish are extremely important, as their numbers are declining in the wild.

The main cause of health problems in these fish is an unsuitable habitat. At the first signs of illness, water parameters should be checked immediately to ensure there are no high concentrations of harmful substances (such as ammonia, nitrites, nitrates, and others). In case of deviations, the parameters must be normalized, and only then should treatment begin. More detailed information on symptoms and treatment methods is presented in the "Aquarium Fish Diseases" section.

When selecting individuals, attention should be paid to the fish's activity and the condition of its skin. A healthy Mystus should have clean fins without signs of erosion or white film, as well as no visible damage or spots on the body. Avoid purchasing fish with sunken bellies or signs of apathy, where the individual lies motionless on the bottom for a long time despite stimuli. Since the species is schooling, it is recommended to acquire a group of several specimens to reduce stress levels during adaptation to a new aquarium.