Shining Pencilfish

Geographic Origin and Biotope: Rio Guamá basin and Capim river (State of Pará, Brazil). Species associated with slow forest environments, "Igarapés", rich in plant sediments, clear but strongly tannic water.

Taxonomy and Morphology: Shining Pencilfish (Nannostomus nitidus). Tiny silvery and slender pencilfish. Profile similar to beckfordi but does not exceed 3.5 cm (1.4 inches) as an adult. Upper jaw slightly more prominent.

Social Behavior: Mild and stationary. Gathers in dense groups in mid-water (Shoaling) near plant barriers, darting away in unison if threatened.

Coloration and Sexual Dimorphism: Elegant but inconspicuous (not "red" or "blue"). Possesses a strong central black stripe, but is topped by a line of a dazzling reflective gold-green (Shining). Males have a red spot strictly confined within the black stripe on the caudal peduncle.

Aquarium Setup: Nano-biotope tank (60 cm / 24 inches). Dark bottoms, light dimmed by floaters and peaty water are essential. Without a darkened tank, their gold-green reflections will be completely lost.

Diet and Feeding: Micro hunter. Needs microscopic slow-sinking foods (micro-pellets for rasboras) or live prey: infusoria and newly hatched nauplii.

Water Quality: Extremely tied to acidic water. If pH rises above 7, they will inevitably fade and stop feeding, falling victim to bacteriosis.

Compatibility and Tankmates: Only ultra-peaceful fish (Boraras, Corydoras hastatus). Their slender build and shyness preclude their breeding in community tanks, especially with dwarf cichlids that would steal the food.

Aquarium Reproduction: Extremely elusive, similar to the other small species of the genus. Scatters tiny eggs in Java moss, but the larvae are too fine to eat nauplii for the first ten days.

Risks and Diseases: Avitaminosis and Fading. They are fed in stores with dry food that is too large for them to swallow. They often arrive at the aquarist's home with a sunken belly and irretrievably debilitated.