Distribution : Rio Araguaia basin, Brazil.
Habitat : Inhabits quiet tributaries off the main river channels, backwaters and oxbow lakes. It often gathers under cover of overhanging or marginal vegetation.
Maximum Standard Length : 0.8" (2cm)
Minimum Tank Size : A standard 18" x 12" x 12" (45cm x 30cm x 30cm) - 42 litre tank is easily big enough for a shoal of these.
Tank Setup : A biotope setup would be very simple to arrange. 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. Aquatic plants are not a feature of this species' natural waters. 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.
Alternatively, it also does well in a well maintained, heavily planted tank. As any of these seen for sale will almost certainly be wild caught a more general setup is not really suitable.
Temperature : 75-82°F (24-28°C)
pH Range : 5.5-7.0. It tends to appear a little pale and washed out when kept in alkaline conditions.
Hardness : 1-10°H
Diet : Omnivorous and will accept just about anything offered. It does have a small mouth, though, so correspondingly-sized foods are best. Feed a mixture of dried flakes and granules and small live and frozen foods. A varied diet, such as this, is essential for the best colour development.
Compatibility : It's a very peaceful species that won't compete well with very boisterous or much larger tankmates. The tiny adult size means it also makes a tasty snack for many commonly kept species, such as angelfish or some gouramis. Ideally, keep it with other quiet South Americans, such as small tetras, pencil fish, Apistogrammadwarf cichlids, dwarf Corydoras and Otocinclus. It could also be combined with smaller cyprinids and Anabantoids if geography isn't an issue.
Always buy a group of at least 6 of these, preferably 10 or more. It is 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.
Sexual Dimorphism : Females are stockier than males, particularly when in spawning condition.
Breeding : Can be bred in a similar way to other species in the genus. You'll need to set up a separate tank if you want to raise decent numbers of fry. Something around 18" x 10" x 10" in size is fine, and you could even get away with something a little smaller. 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 80-84°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.
It can be spawned in a group, with half a dozen specimens of each sex being a good number. Condition these with plenty of small live foods and spawning should not present too many problems.
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.
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 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.
