Has been recorded from major river channels, smaller tributaries, and floodplain lakes, many of which comprise acidic, mineral-poor blackwater environments with brownish, tannin-stained water, although it has been observed to inhabit clear waters as well.

Many of its habitats lie within the Venezuelan and Colombian llanos, a vast, highly biodiverse system of tropical savannah grasslands, seasonally-flooded plains and forests covering an area measuring almost 600,000 square kilo…

At least two colour forms have been traded, one of which is more intensely-coloured and has been referred to as H. sweglesi ‘red’ or ‘rubra’. The bright red pigmentation is retained in long-term captive specimens, suggesting that it is not considered to be an artefact of diet, but we suspect it might reflect conditions at the collection locality with the reddest fish putatively inhabiting blackwater and plainer forms clearwater environments. Zarske (2014) found the two forms to be identical in terms of morphology an…

A beautiful species that's not often seen for sale in the hobby, and is usually a little more expensive than other tetras when available. This is mainly due to the wild caught nature of most specimens entering the trade. It can be a little delicate when initially imported, and is sensitive to deteriorating water conditions in general. As a result, it's not a good choice for the beginner, and should only be added to well-matured tanks.

As with the closely related Hemigrammus, the ta…

S. daemon is relatively common in the aquarium trade but is by no means easy to maintain, with particular attention to space, diet, water quality, and chemistry required in order for it to thrive.

It can be distinguished from other members of the genus by possessing two dark blotches on the flank and a prominent ocellus at the caudal-fin base. Among the named species it is most similar to…