|Distribution||Rio Negro & Rio Meta Basins, Brazil & Colombia.|
|Sexual Dimorphism||Difficult to distinguish. Males are usually slightly slimmer than females.|
|Maximum Size||4cm (1.58”)|
|Water Parameters||The natural conditions of this species are very soft & acidic blackwaters. Aquarium bred fish are less demanding pH: 5.5-7.5, dH: 1-18 degrees|
|Temperature||22-28 deg C (72-82 deg F)|
|Lighting||No special requirements|
Rummynose tetras are naturally found in forest creeks where leaflitter and detritus stain the water dark with tannins. In these soft, acidic blackwater habitats they swim in large shoals and this sociable nature means that they should be kept in good numbers in the aquarium. Aquatic plants are rare in their natural environment, but dead leaves carpet the ground – most shade and shelter is provided by bankside growth or floating plants.
Although the fish seen in our stores are tank bred in less extreme conditions, ‘rummies’ are at their best in acidic water and will show their best colours when the pH is low. When kept in more alkaline conditions, parameters such as nitrate become more problematic and may cause a significant loss of colour as a first symptom of stress. As with many blackwater species, the higher background bacterial populations in hard, alkaline water may be challenging for them, making good maintenance and hygiene very important.
Found alongside species such as stingrays and cardinals in the wild, these tetras are extremely peaceful and can be housed with a wide range of fishes that enjoy the same conditions. They are particularly striking when kept as a shoal of twenty or more and mix well with discus in large aquaria.
As the most widely kept and bred of the three rummynose species, a number of aquarium forms have been produced, including a platinum form with increased iridescence, an albino and a golden xanthic strain. P. bleheri may also be referred to as Firehead tetra but this is unlikely to appear on a shop label. Two related species are occasionally imported - Ahl’s Rummynose Tetra (P. rhodostomus) and the False Rummynose Tetra (P. georgiae) and these should be kept in the soft, acidic conditions they’d inhabit in the wild. Recent changes have seen all the Rummynose moved into the same genus - from Hemigrammus into Petitella.