Brown Pencilfish

About

The brown pencilfish (Nannostomus eques) is one of the more characterful members of a group already known for slender builds and gentle dispositions. Native to the central and upper Amazon basin, it lives among dense vegetation in soft, often acidic blackwater environments. What immediately sets it apart from its relatives is its habitual swimming angle. It holds itself at a distinct nose-up tilt, a trait shared among pencilfish only with the closely related one-lined pencilfish. Coloration follows a classic pencilfish pattern: a dark brown lateral stripe running from snout to tail, overlaid with silver-grey above and tiny dark spots freckling the scales below the stripe. At one to two inches fully grown, it is a genuinely small fish, and that size demands some thought about tankmates. This is a peaceful species but can be easily outcompeted or intimidated by anything boisterous. It works well alongside similarly small characins, diminutive catfishes, and makes a surprisingly good companion for Apistogramma and other dwarf cichlids, occupying the upper water column without threatening their fry. Keep it in groups of ten or more if you can. Larger numbers encourage bolder behavior and distribute any low-level male rivalry harmlessly. Breeding is possible in a well-planted aquarium but requires some patience and a controlled setup to raise meaningful numbers of fry.