Approuague basin

This species is also referred to as 'velvet cichlid', 'red oscar', 'tiger oscar', or 'marble cichlid'. It is a popular aquarium fish although its adult size and typical life-span of 10-20 years must be taken into account before purchase. Numerous ornamental strains are now available, and while care is more-or-less identical for all of them a degree of additional care must be taken with the 'long-finned' variety which is a little less competitive than other forms.

Most Astyanax spp. are not popular in the aquarium hobby, though the genus is among the most speciose within the family Characidae. A. leopoldi is no exception in that you'll rarely see it offered for sale but may find the occasional specimen mixed among other species in shipments of wild fishes from Peru.

In a study conducted on the Arataye River, the main tributary of the Approuage, this species was mostly collected from stretches of rapids with rocky substrate which were reduced to a series of pools during the dry season. Other fishes observed at the same site were Auchenipterus nuchalis, Hypostomus gymnorhynchus and Moenkhausia cf. intermedia while at other localities in the river Bryconops affinis, Myleus ternetzi, M. rhomboidalis, Moenkhausia aff. barbouri, Curimata sp. and Serrasalmus sp. were collected.

This species is uncommon in the aquarium trade although its name is sometimes applied to other species. It was originally described in the monotypic genus Pseudopristella, and can be distinguished from the vaguely similar Pristella maxillaris by possession of a relatively large (vs. relatively small) humeral spot and having black pigmentation in the anal-fin restricted to the first ray (vs. a prominent distal blotch).

This is the type species of the genus, fairly ubiquitous in the aquarium trade, and represents an excellent choice for the newcomer to fishkeeping since it's less demanding than most congeners. It's sometimes referred to as 'Beckford's pencil fish' or 'brown pencilfish'. Don't worry if your fish look different when you switch on the aquarium lights after dark or in the morning as like most Nannostomus species it assumes a cryptic, vertically-barred colour pattern at ni...

Based on current knowledge, it thus remains impossible to deduce whether the group of putative species currently comprising S. jurupari, S. mapiritensis, and S. rhynchitis, plus populations from Amapá and the upper Negro/upper Orinoco region, represent distinct taxa or a single meta-population which can be referred to as S. jurupari sensu lato. Here on SF we include the named species separately, since they continue to be considered valid.

H. borealis is a member of the putative ‘H. heterorhabdus-group’ of closely-related species within the genus as proposed by Géry (1977). There are around 15 members characterised by a 'longitudinal pattern' consisting of a thin, usu...