Aquarium Kings – that is the title given to a few of the most stunning aquarium fish on the planet – discus (Symphysodon sp.). These fish instantly appeal to the attention resulting from their extraordinarily uncommon, nearly spherical, physique form and enchanting coloration, particularly in quite a few breeds. The fish have been referred to as discus fish for his or her flattened, disk-like physique.
The genus title consists of two Greek phrases symphysis – “fused” and odon – “tooth”. And that is as a result of peculiarity of the situation of the 4 excessive enamel, positioned on the junction of the higher and decrease jaws, one beneath the opposite. The title “Diskus” appeared a bit of later. This phrase in historic Greece meant a flat throwing projectile for competitors.
Discus has a sure specificity of preserving: steady water parameters, elevated temperature, the necessity for big volumes for preserving. They might be referred to as extraordinarily delicate, which discourages many aquarists from preserving these lovely fish. The low immunity of discus is related to their pure habitat. The water within the Amazon basin may be very smooth and acidic and accommodates numerous tannins. In such water, the copy of microorganisms is tough, due to this fact, discus shouldn’t be in a position to correctly reply to infections. Thus, a discus is advisable for preserving by skilled aquarists, who completely perceive all of the processes happening within the aquarium.
Discus was first described by Australian scientist Johan Natterer throughout his subsequent expedition to Brazil. It occurred in 1833 after a specimen of a beforehand unknown fish was caught within the Rio Negro River. Johan Jacob Heckel made an excellent contribution to the research of discus, it was he who proposed the generic title Symphysodon.
The first dwell discus was launched to Europe in the course of the twentieth century. Currently, due to the mass breeding of fish in particular complexes, it’s not tough to purchase them virtually in any nation. But it must be famous that the value of discus stays one of many highest. Especially with regards to a uncommon shade variation.
The physique of the discus has a disc-like form and may be very strongly compressed from the perimeters to the purpose that when observing the fish from the aspect of the caudal fin, one can see two eyes protruding from the perimeters of the pinnacle. These eyes are massive and are positioned on a small head. The fins might be clear or have coloured spots in the identical shade because the physique. The caudal fin is fan-shaped; the dorsal and anal fins run from head to tail. The pelvic fins are elongated. In the grownup male discus, a distinctly distinguished brow might be noticed. The shade is extraordinarily assorted and relies on the particular species, however it’s at all times efficient. It can change relying on the state of the fish: coloured stripes can seem or disappear all around the physique. In an aquarium, discus can develop as much as 25-30 cm.
The homeland of discus is the rivers of South America. They are discovered within the Amazon Basin. Therefore, discus might be present in nations resembling Brazil, Colombia, Venezuela, and Peru.
The biotopes of the Amazon Basin are very attention-grabbing and may endure vital adjustments. In December, the wet season begins, which results in flooding of rivers, because of which large areas are flooded. Floods carry loads of turbidities, and the beforehand crystal clear waters turn out to be like a swamp. After the top of the lengthy rains, the water stage drops, it turns into clear once more. Quiet backwaters seem in every single place, by which the water acquires a darkish shade (“black water”). In such remoted areas, the water is extraordinarily smooth and acidic. It is in such situations that debate lives within the wild. They favor to remain nearer to the coast, dwell in thickets of bushes. The backside in such reservoirs is a thick layer of decaying leaf litter. Most of the life and spawning of fish takes place among the many roots of coastal vegetation. It must be famous that it is rather uncommon to seek out discus fish in massive rivers; they like small streams and tributaries. As a results of this isolation, native shade populations of discus fish have emerged, and we are able to observe a powerful number of colours of those superb fish.
The taxonomy of the discus has undergone sure adjustments in the course of the research of the lifetime of fish. At first, all discus have been attributed to the identical species, contemplating the variations in shade to be solely shade variations. But a extra detailed examination of the options of those fish led to the identification of three species inside the genus Symphysodon.
- Red discus (Symphysodon discus)
This kind of discus was the primary to seem in hobbyist aquariums. In honor of the scientist who first described this species, it’s typically referred to as the Heckel discus.
They dwell in South America, within the Amazon River Basin: specifically, within the Rio Negro, Rio Branco, and different rivers. They favor water wealthy in humic substances, the so-called “black water”. The soil in pure biotopes is sandy with numerous dying leaves.
The form of the physique is normal, disc-shaped, flattened laterally. The iris of the eyes is brilliant crimson. The physique shade of the Heckel discus ranges from reddish yellow to brown. Longitudinal wavy blue traces cross nearly your entire physique of the fish, apart from the chest and center of the physique. There are 9 vertical darkish stripes on each side of the flattened physique, the primary, fifth, and ninth stripes are most pronounced (brighter and wider). Depending on the situation of the fish, the colour of the discs might fluctuate.
If the fish is agitated, the vertical traces virtually disappear, however the blue ones turn out to be a lot brighter. In worrying conditions or with poor content material, all the things occurs precisely the other: the blue traces fade, and the vertical ones turn out to be extra distinction. In particularly superior conditions, an nearly full discus discoloration might be noticed. In nature, it grows as much as 20 cm, in aquariums, the scale normally doesn’t exceed 10-15 cm. Sexual dimorphism is weakly expressed. The pure eating regimen relies on zoo and phytoplankton, in addition to detritus throughout dry durations.
- Green Discus (Symphysodon tarzoo)
Despite the truth that the principle physique shade of the fish is brown-yellow when analyzing a fish caught in nature with a mirrored image of a blue sky, the scales seem greenish. The fish acquired a selected epithet in honor of the Colombian firm from town of Leticia, specializing within the export of fish. It was in its neighborhood that Symphysodon tarzoo was caught and described. It must be famous that this group of discus acquired the standing of a species comparatively lately – in 2006, based mostly on DNA evaluation.
The inexperienced discus inhabits the Amazon River basin (Peru, Colombia, Brazil). They favor black water. They dwell close to the coast amongst sunken bushes and dying leaf litter.
The iris is brilliant crimson. Longitudinal wavy traces of turquoise shade run alongside your entire physique and dorsal fin of the inexperienced discus. A large black stripe runs alongside the dorsal fin. Morphologically, any such discus differs from others by the presence of reddish dots on the physique and fins, which seem in fish on the age of six months. Sexual dimorphism shouldn’t be pronounced. The common dimension of a inexperienced discus in an aquarium is 13 cm.
- Discus equidistant (Symphysodon aequifasciatus)
The Discus is inhabited within the basins of the Amazon and Rio Negro rivers. They favor clear water. The size reaches 15 cm. The head and mouth are small. The physique is disc-shaped, with a wavy sample on it. The background shade of the fish varies from brownish-yellow to crimson. Horizontal stripes are blue or greenish. A large darkish stripe runs alongside the dorsal and anal fin in a semicircle. Body-color might fluctuate relying on the situation of the fish. Distinguishing a feminine discus from a male is kind of problematic.
There are a number of subspecies of Symphysodon aequifasciatus with a attribute coloration – brown and blue discus. Determining the precise kind of discus in an aquarium is nearly unattainable resulting from the truth that a few years of labor by breeders have led to the looks of numerous shade variations. Sexual dimorphism in these fish shouldn’t be expressed.
Care and upkeep
To preserve discus, to start with, you want a spacious aquarium. The minimal quantity for a small college of fish is 250 liters, however ideally, this must be an aquarium of 400 liters or extra. The peak of the water column is fascinating about 50 cm since discus is a comparatively tall fish in an grownup state. When preserving discus fish, it is rather vital to offer peace of thoughts to pets. Fish are very shy and fixed stress components can result in sickness and even demise. It shouldn’t be advisable to arrange an aquarium with discus in walk-through areas or close to sources of robust sounds.
There are two primary approaches to the inside of an aquarium when preserving discus. Some aquarists favor the traditional model – a natural aquarium with soil and dense thickets of crops.
Others imagine that discus doesn’t want a further background, and it’s higher to maintain them in an aquarium with out soil, crops, and decorations. The latter perspective is extra sensible and is related to the truth that, firstly, it’s tough to seek out crops that may face up to the optimum temperature for discus (27-30 ° C). Secondly, any dying natural matter within the aquarium is a possible supply of nitrogenous compounds, to the content material of which the discus are very delicate.
On the opposite hand, a natural tank with discus appears to be like way more spectacular, and dwell crops assist keep the organic steadiness within the aquarium. The most vital factor is cautious upkeep, the availability of carbon dioxide, high-quality lighting.
Discus doesn’t tolerate any fluctuations in water parameters. The extra steady the surroundings, the much less doubtless these fish are sick. Discus are extraordinarily thermophilic: the optimum temperature is 27-30 ° C. The water must be acidic and smooth, near that in nature. pH = 5.5 – 6.5, hardness – 1 to 12 ° dGH.
The aquarium must be supplied with high-quality filtration (highly effective exterior filter and even a number of) and aeration. An enhance within the content material of nitrates in water above 25 g / l should not be allowed. Discus are very delicate to the focus of nitrogenous compounds, and exceeding the norm may cause stress. A weekly change of as much as ¼ of the aquarium water is required. Although there’s a suggestion that it’s advisable to do a each day water change of 10-20%. In this case, every aquarist decides for himself how greatest to proceed. The primary factor is to recurrently take a look at the water for primary parameters and forestall their sudden jumps. With excellent care, discus can dwell in an aquarium for 10 to 18 years.