Order Siluriformes
Family Heteropneustidae (Air sac catfishes)
They have 4 pairs of rather long barbels directed forward and a short dorsal fin. The role of a peculiar lung is played by a pair of cylindrical air sacs extending from the gill cover to the tail. Without access to atmospheric air, the catfish dies within 5-7 hours.
Genus Heteropneustes.
A top bestseller is the stinging catfish (Heteropneustes fossilis). If the temperament of this “funny beast” matched its appearance, it would be priceless! Oh, how they call it! A cleaner, a scavenger, a waste collector… That’s all almost true, just keep in mind that what it will clean and then scavenge is your other fish. It grows up to 60 cm.
Nine out of ten pet store sellers will argue to you that this is a dwarf form. And only with proper care, and if the fish do not die in their first year of life, will you be able to see for yourself the opposite — catfishes grow and very quickly! There is only one reason why even the largest fish become “stunted” and do not reach their natural size: a small aquarium and many other large fish.
— Asian Stinging Catfish, Fossil Catfish, Stinging Catfish — Heteropneustes fossilis [Bloch, 1794]. Synonyms: Silurus fossilis, biserratus, Saccobranchus microcephalus. (English: Asian Stinging Catfish, Fossil Catfish, Liver Catfish, Stinging Catfish). Inhabits water bodies of Sri Lanka, India, Burma, Laos, Thailand, Vietnam. Large specimens reach 30-40 cm. The body is very elongated, eel-like, wriggling serpentinously when swimming. The pointed, small head has four pairs of long, movable barbels directed forward, eyes are small. The anal fin is long, the rest are small and rounded.
The dorsal and pectoral fins bear sharp spines containing venom. Caution should be exercised when catching stinging catfishes, as the spines of the pectoral fins can inflict slow-healing punctures. Their stings are very painful and resemble a bee sting, so caution is necessary primarily for people prone to allergies.
This species is capable of breathing atmospheric air for a long time. On the sides from the gill covers to the tail, there are two cylindrical sacs stretching along both sides of the back along the entire body, their walls permeated with a large number of blood vessels (thanks to them, the catfish can leave the water or burrow into the silt). If the fish is deprived of the opportunity to breathe atmospheric air, it will die in 5-10 hours.
Colored in dark grey, grey-black, violet-brown or brown tones. During spawning, the coloration changes to mottled. In the adult stage, they turn black. Albino and veil forms exist, as well as specimens with golden longitudinal stripes. The albino form is most commonly available in trade. Juveniles have a disproportionately large head and do not look like their parents until they reach 5 cm in length. The male is smaller than the female and more slender.
The fish is undemanding, omnivorous. It picks up organic remains from the bottom, thereby acting as a scavenger. Fish lead a nocturnal, solitary lifestyle, preferring dimly lit areas in the aquarium, crevices and shelters. Medium-sized fish are suitable for a community aquarium. Extremely territorial, pugnacious. Shelters are required. Predatory fish. It even attacks fish larger than itself. It is best kept in a species aquarium. It can be introduced into a community aquarium only with large specimens (the catfish views the rest as food). Prefers a solitary existence.
Aquarium with a volume of 150 liters or more with various shelters (driftwood, caves), dense planting, and open swimming space. The aquarium should be covered, as at night catfishes often jump out while frolicking. Lighting is diffused. Substrate is fine gravel. Raging in the substrate, it muddies the water. Filtration, aeration, and weekly water changes are required.
Consumes any live food — live feeder fish, shrimp, pieces of fish, mollusks, insects, traditional sinking frozen and dry foods. Swallows prey whole. Reaches sexual maturity at the age of 1-1.5 years, when males are typically 6 cm and females 12 cm. At this time, the coloration changes to mottled. At 1.5 months, juveniles reach a length of 5 cm. Lifespan is 10 years. dH up to 20°; pH 6.5-8.0; T 21-25°C.
— Heteropneustes microps [Gunther, 1864]. Southeast Asia. 15-30 cm. Body very elongated, eel-like. The pointed small head has four pairs of long movable barbels directed forward. Fins have sharp spines, the stings of which are very painful. Fish lead a nocturnal solitary lifestyle, prefer dimly lit areas in the aquarium, crevices and shelters. Shelters are necessary. Filtration, aeration, weekly water changes. House only with commensurately sized fish. pH 6.0-8.0; T 22-26°C.
Aspredo aspredo, Platystacus cotylephorus, Bunocephalus coracoideus, verrucosus.
Brachyrhamdia imitator, Brachyrhamdia meesi, Brachyrhamdia rambarrani. 
