Hemigrammus vorderwinkleri

Classification

Characidae

Distribution

Known only from the Rio Negro, Brazil.

Habitat

Blackwater rivers and tributaries. The water in these biotopes is typically stained brown with tannins from decaying organic material and is very acidic as a result.

Maximum Standard Length

1.4″(4cm).

Aquarium SizeTop ↑

A standard 24″ x 15″ x 12″ (60cm x 37.5cm x 30cm) – 70 litre tank is suitable for a small shoal.

Maintenance

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.

Water Conditions

Temperature: 74-80°F (23-27°C)

pH: 5.5-7.0

Hardness: 1-12°H

Diet

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 other Hemigrammus or 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 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

Adult males are slimmer and usually slightly smaller than females. The anal fin of males is also hook-shaped.

Reproduction

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. 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 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.

NotesTop ↑

The only time you’ll probably come across this species is as a contaminant among imports of other species. This is a pity, as it’s an attractive, peaceful little fish.

Like all Hemigrammus, the taxonomic status of this species is currently Incertae Sedis, meaning uncertain. The genus is currently used as something of a catch-all for over 70 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.