Family: Lebiasinidae
Dwarf Pencilfish — a Lebiasinidae from South America, peaceful mid-water shoaler; confidence comes in numbers. Reaches 2.6–3.9 cm; groups of 8 minimum; more is visibly better. 24–26 °C.
A Lebiasinidae species native to South America: Nannostomus marginatus lives bottom-dwelling over warm freshwater streams and lakes. Peaceful mid-water shoaler; confidence comes in numbers. Adults reach 2.6–3.9 cm. It is one of the aquarium-kept Nannostomus species we profile, alongside Nannostomus beckfordi, Nannostomus eques, Nannostomus harrisoni.
Difficulty: moderate. Peaceful mid-water shoaler; confidence comes in numbers. Groups of 8 minimum; more is visibly better.
Set the heater to 24–26 °C and avoid swings. pH 5.8–7.5, GH 5–19 dGH suit it.
Expect 2.6–3.9 cm as an adult, living bottom-dwelling. A 25 L tank or larger gives it room.
Small omnivore; quality flakes and small frozen foods. Vary the menu — quality flakes or pellets plus frozen or live foods.
Peaceful mid-water shoaler; confidence comes in numbers; groups of 8 minimum; more is visibly better. Good company: Other small peaceful tetras and rasboras — Form a mixed, calm mid-water mass. Keep away from Single-species isolation — A lone tetra is a stressed tetra.
Its home waters are South America — warm freshwater streams and lakes, with still to gentle current.
Jumping is not a known issue; cover the tank anyway during water changes.
In the aquarium: typical egg-scattering characin; adults eat the eggs. Subtle external differences.