Brachychalcinus Orbicularis

Datasheet

General Description

The Discus Tetra, scientifically known as Brachychalcinus Orbicularis, is a relatively uncommon species in the aquarium trade. Belonging to the Characidae family, this tetra is categorized under the Characiformes classification order. It is one of the five species within the Brachychalcinus genus and is often referred to as the 'silver dollar tetras,' though precise identification can be challenging due to similarities within the genus. Adult specimens can reach a maximum size of approximately 9.0cm.

Aquarium Setup

Maintaining the Discus Tetra in a well-kept aquarium involves mimicking its natural habitat. This species thrives in environments resembling lowland rivers and creeks. Therefore, setting up the tank to resemble a flowing stream or river with a substrate of varied-sized rocks, sand, fine gravel, and driftwood is recommended. The addition of aquatic plants, although preferred, should include varieties with tougher leaves to prevent nibbling. Regular water changes of 30-50% tank volume and ensuring a high proportion of dissolved oxygen with moderate water movement are vital for the well-being of these tetras. Specific water conditions include a hardness range of 18-215ppm, a pH level of 5.0-7.5, and a temperature range between 20-27°C.

Behaviour

The Discus Tetra is generally peaceful but can exhibit intimidating behavior towards smaller or more timid species due to its relatively large size and slightly vigorous nature, particularly during feeding times. This species tends to thrive in larger community tanks, preferably alongside similarly-sized fish such as certain characids, cichlids like Geophagus or Heros spp., callichthyid, and loricariid catfishes. Being a schooling species by nature, acquiring 8-10 specimens is ideal. Maintaining them in decent numbers not only reduces skittishness but also promotes a more natural group dynamic, mitigating aggressive behavior as the tetras establish their hierarchy within the group.

Feeding and Diet

In the wild, the Discus Tetra is known to be an opportunistic omnivore, feeding on various aquatic invertebrates, insects, algae, and plant matter. In aquarium settings, they readily accept a diet consisting of small live and frozen foods like bloodworms, Daphnia, and Artemia, supplemented with high-quality dried flakes and granules. It is crucial to provide some plant or algal content within their diet for optimal health and vibrant colors.

Reproduction & Dimorphism

Details on the reproductive behavior of the Discus Tetra are scarce, but spawning can occur in large aquaria, with a single female capable of laying up to 2000 eggs. During spawning, dim lighting and a suitable substrate for egg dispersion are essential. Post-spawning, adults should be removed to prevent predation on the fry. Sexual dimorphism in this species includes females growing slightly larger and displaying a rounder belly when gravid, while males feature small hook-like extensions on their anal fin rays.

Habitat and Distribution

The Discus Tetra is primarily found in the coastal watersheds of Guyana and Suriname, with its type locality documented in the Essequibo River, Guyana. Recent observations suggest the species, or a similar-looking relative, may also inhabit the Río Orinoco and Río Negro drainages in Venezuela and Brazil. These tetras typically inhabit lowland rivers, creeks, and tributaries, with occasional sightings in pools or impoundments.