Originates from the lower Amazon basin in Brazil.
Small tributaries, creeks, areas of flooded forest and sand banks. The water in these biotopes is often stained brown with tannins and other chemicals released from decaying organic material, and is very acidic as a result.
Maximum Standard Length
Around 1.6″ (4cm).
Aquarium SizeTop ↑
If you really want to see it at its best, you could set up a biotope tank. Use a substrate of river sand and add a few driftwood branches (if you can’t find driftwood of the desired shape, common beech is safe to use if thoroughly dried and stripped of bark) and twisted roots. A few handfuls of dried leaves (again beech can be used, or oak leaves are also suitable) would complete the natural feel. Allow the wood and leaves to stain the water the colour of weak tea, removing old leaves and replacing them every few weeks so they don’t rot and foul the water. A small net bag filled with aquarium-safe peat can be added to the filter to aid in the simulation of black water conditions. Use fairly dim lighting. Under these conditions it will develop its most intense colouration.
Temperature: 74-82°F (23-28°C)
pH: 5.5-7.5. Although it will survive in slightly alkaline water, it tends to be more colourful when kept in acidic conditions.
Feeds chiefly on small invertebrates in nature. In the aquarium, it proves unfussy. Feed a mixture of dried flakes and granules along with small live and frozen foods.
Behaviour and CompatibilityTop ↑
It’s a very peaceful species that won’t compete well with very boisterous or much larger tankmates. Ideally, keep it with other South American species, such as Hemigrammus or other Hyphessobrycon species, pencil fish, Apistogramma dwarf cichlids, Corydoras and small Loricariids. In a more general community, it can be combined with smaller rasboras, barbs, Anabantoids and West African dwarf cichlids such as Pelvicachromis species.
Always buy a group of at least 6 of these, preferably 10 or more. It’s a shoaling species by nature, and will fare much better when in the company of its own kind. Like most tetras it actually looks far more effective when maintained like this anyway.
Quite easily bred, although you’ll need to set up a separate tank in which to do so if you want to raise any numbers of fry. Something around 18″ x 10″ x 10″ in size is fine. This should be very dimly lit and contain clumps of fine-leaved plants such as java moss or spawning mops, to give the fish somewhere to deposit their eggs. Alternatively, you could cover the base of the tank with some kind of mesh. This should be of a large enough grade so that the eggs can fall through it, but small enough so that the adults cannot reach them. The water should be soft and acidic in the range pH 5.5-6.5, gH 1-5, with a temperature of around 75-80°F. Filtering the water through peat is useful, as is the use of RO water. A small air-powered sponge filter bubbling away very gently is all that is needed in terms of filtration.
Alternatively, it can be spawned in pairs. Under this technique, the fish are conditioned in male and female groups in separate tanks. When the females are noticeably full of eggs and the males are displaying their best colours, select the fattest female and best-coloured male and transfer them to the spawning tank in the evening. They should spawn the following morning. Interestingly, during the act itself the pair often turn completely upside down.
In either situation, the adults will eat the eggs given the chance and should be removed as soon as eggs are noticed. These will hatch in 24-36 hours, with the fry becoming free swimming a 3-4 days later. They should be fed on an infusoria-type food for the first few days, until they are large enough to accept microworm or brine shrimp nauplii. The eggs and fry are light sensitive in the early stages of life and the tank should be kept in darkness if possible.
This species is not particularly popular in the trade, a pity as when in good condition it’s a very good looking little fish. It’s sometimes confused with the similar looking black neon tetra, H. herbertaxelrodi, but is easily distinguished as it possesses an extra, red lateral stripe which is not present in the black neon.
As with the closely related Hemigrammus, the taxonomic status of all species in the genus Hyphessobrycon is currently Incertae Sedis, meaning uncertain. The genus is currently used as something of a catch-all for over well over 100 species of small characin. Most experts agree that a full revision is required, with the likely outcome that many species will be placed into new or different genera. H. heterorhabdus, for example, belongs to a small species ‘complex’ often referred to as the ‘heterorhabdus-group’. This comprises half a dozen or so very similar species with a narrow longitudinal band along the body.