Two-striped Pencilfish (Nannostomus bifasciatus) Breeding Guide

How to breed Nannostomus bifasciatus: an egg-scattering pencilfish from Suriname and French Guiana whose adhesive eggs attach to plants and receive no parental care.

Overview

Nannostomus bifasciatus Hoedeman, 1954 is a small lebiasinid pencilfish recorded from the coastal rivers of Suriname and French Guiana, reaching about 3.4 cm standard length (FishBase). According to FishBase, the species breeds in captivity; its eggs are adhesive and attach to plants but receive no parental care. Within the genus Nannostomus, Wikipedia notes that most species will spawn in a thickly planted single-species aquarium, the eggs are not eaten, and fry are later found among the plants.

Sexing

Detailed sexing data specific to N. bifasciatus is limited in the sources opened. Across the genus, mature males of Nannostomus are typically slimmer and more intensely coloured than females, while ripe females are deeper-bodied; the documented behaviour for this species is gregarious schooling in groups of about a dozen individuals (FishBase).

Conditioning

Source-specific conditioning protocols for N. bifasciatus were not located. The genus-level approach reported by Wikipedia is to maintain a thickly planted, single-species tank with soft acidic water, where well-fed adults spawn without special intervention. FishBase lists an environmental range of pH 5.5-7.0, hardness up to 4 dH and 23-27 degrees C for the species.

Breeding Setup

Because the adhesive eggs attach to plants and are not guarded (FishBase), a densely planted aquarium with fine-leaved vegetation gives eggs and emerging fry refuge, consistent with the genus pattern in which fry are found growing among the plants (Wikipedia). Soft, acidic water within the species range of pH 5.5-7.0 and up to 4 dH is appropriate (FishBase).

Spawning Behavior & Trigger

Specific spawning triggers for N. bifasciatus are not documented in the opened sources. The genus generally spawns spontaneously in a suitable thickly planted tank rather than after a single induced trigger (Wikipedia), with eggs adhering to plant surfaces (FishBase).

Egg & Fry Care

The eggs receive no parental care (FishBase). In the genus, fry are subsequently found developing among the plants in the breeding aquarium (Wikipedia). Detailed first-food schedules for this particular species were not present in the sources opened, so they are omitted here.

Common Challenges

As with related pencilfishes, the main challenge is providing dense planting so unguarded, adhesive eggs and tiny fry are not consumed, and maintaining the soft, acidic conditions reported for the species (FishBase).