Aquarium fish: Heteropneustes fossilis (Heteropneustes fossilis)
Size: 25 – 30 cm
Water temperature: 21-25 ° C
Aquarium volume: 280 l
Heteropneustes fossilis (Heteropneustes fossilis ) – the only representative of the Heteropneustidae family. In Bangladesh, it is caught for consumption. Imported to Europe, it did not live up to expectations due to the slow growth rate and excessive voracity. This species is also valued and important in medicine – the treatment of malaria.
It is found in the waters of Sri Lanka, India, Burma, Bangladesh and southern Vietnam. It lives in ponds, canals, wetlands, flood plains and cloudy rivers. This fish is probably able to survive in any aquatic environment. It also tolerates slight salinity. In the dry season, it lives in half-dried mud.
And if the substrate is completely dry, it slides into the lower parts of the wet gaps.
Characteristics and disposition
In the natural environment, it reaches up to 31 cm in total length, in an aquarium it is usually slightly shorter. The shape of the body is eel-shaped, with a broad, flattened head. Mouth opening at the end, pointing forward, surrounded by four pairs of whiskers. Sexual dimorphism is poorly visible .
Adult females are stockier. Coloration of the body is gray-brown or olive-brown, darkening to black with age. On the sides, two pale, longitudinal stripes and numerous black spots. Anal fin long – from 60 to 79 rays. Ventral fins – 6 rays.
H. fossilis pectoral fins have 8 rays. The first ray is most developed and transformed into a serrated, harpooned spike. There are three articulating surfaces at the base of the spike that enable locking when raised. In males, next to the spines of the dorsal and pectoral fins, there are single-celled venom glands.
The composition of the venom is not fully known, but it does contain substances that cause swelling and necrosis in the surrounding tissues. According to some scientists, it may also show cardiotoxic effects. Be very careful when working in the aquarium and catching these fish. If an injection occurs, it is recommended to immerse the wound in warm water and administer painkillers. Sometimes, surgical assistance and an ECG are necessary.
Indian catfish, similarly to the fish of the Clariidae family , are equipped with a special suprillary organ – two long, hollow, cylindrical, not too strongly bloodied sacks running along the spine, one on each side of the body, up to the tail shaft. Thanks to it, they can breathe atmospheric air. Additionally, their body produces large amounts of mucus. These two abilities enable them to cover considerable distances on land, e.g. in order to change a water reservoir, search for a mate or for food.
They lead a nocturnal, bottom-line lifestyle. Opinions about temperament are divided. Rather, they do not show aggression, but may occur in individual cases or in aquariums that are too small. Certainly, fish that fit into their mouths will be treated as food.
Nutrition and feeding
The basis of the diet should be foods of animal origin, e.g. insect larvae, crustaceans, earthworms, frozen shrimps, crickets and good quality dry foods that sink to the bottom. Interestingly, they can also learn to eat cichlids from the surface of the water.
Due to their size, they need a lot of space to swim. The size of the bottom surface is more important than the height of the tank.
They require soft, sandy ground and numerous hiding places. Dry roots, bark, branches and leaves can be used to decorate the aquarium. At the discretion, plastic tubes or pots will also be suitable. Due to the possibility of leaving the aquarium, a tight cover and a slightly lower water level are necessary. Lighting and plants are not necessary, but you can, for example, leave one part of the tank dimly lit and plant some sturdy, tough plants.
Hardy fish that can tolerate a wide range of water parameters and even light salinity. Due to their high appetite, they require efficient filtration. They can be kept with larger and active fish that will not fit into their mouths. Free-swimming species that need peace of mind will be harassed and stressed by their high nocturnal activity. For example, large barbs and other similar fish will be a good company.
They like the company of their own kind very much.
They are happy to breed in aquariums. They reach sexual maturity after about a year – then the male is usually 5.5 cm, and the female is 12 cm. A separate tank, arranged as described above, is required for spawning. We stimulate spawning by mapping the seasons, i.e.
dry and rainy seasons. Over the course of 3-6 weeks, gradually pour out the water and raise the temperature. During this time, we increase the amount of live and frozen food served. Then we start adding water obtained from the RO filter – the total hardness should not exceed 3 dGH. In too hard water, the fertilization and development of eggs is difficult.
22ºC is the optimal temperature for breeding. Males start their courtship in the afternoon. Usually, in the evening of the same day, spawning takes place. The male forms a U-shaped body, embraces the flowing female, which releases the eggs and is fertilized. Small 2 mm, sticky, yellow-green eggs are placed in clusters into previously prepared depressions in the substrate.
An adult female lays 3,000 to even 45,000 eggs, depending on the size of the fish. A female weighing 100 g on average lays 8,000 eggs. Parents take care of the roe and fry. Until hatching, they fan the roe with their fins, ensuring the necessary circulation and supply of fresh, oxygenated water. After hatching, they protect the young for about a month.
Roe is sensitive to mold. Hatching depends on temperature and takes 18-24 hours. For 4-5 days, the larvae feed on the contents of the yolk sac. After this time, start feeding. In the first period of life, artemia larvae and crushed dry food may be given.
The fry grows quickly. Within a month, it reaches 8 cm in length.