Barred pencilfish

Geographic Origin and Biotope: Mazaruni River Basin (Guyana). Inhabits shaded forest streams (Igarapés), where slow, crystal-clear waters flow over beds of sand and fallen branches.

Taxonomy and Morphology: Espe's Pencilfish / Barred Pencilfish (Nannostomus espei). Among the rarest pencilfish on the market. Tiny torpedo morphology, almost completely lacks the long central black stripe, typical of the genus.

Social Behavior: Peaceful school (Shoaling). Very stationary in mid-water. Unlike beckfordi, males exhibit few skirmishes, spending time in tight inclined or horizontal formations inspecting leaves.

Coloration and Sexual Dimorphism: Unique "comma" pattern: instead of the horizontal line, it has 5 large oblique black spots/commas ("barred") arranged on the light flanks with gold reflections. This pattern serves to camouflage among fine debris. Males are slenderer and have dark tips on the anal and dorsal fins.

Aquarium Setup: Biotope for specialists. Minimum tank 60 cm (24 inches). Very weak sponge filter, lots of Cryptocoryne, Echinodorus or Moss. Dim light is mandatory to make them come out in the open.

Diet and Feeding: Mid-water micropredator. Requires extra-small granules (less than 0.5 mm), newly hatched live brine shrimp, and frozen Cyclops. They will refuse bites that are too hard or large pieces.

Water Quality: Requires pristine and stable waters. Ph 6.0 and low GH. Although it comes from clear waters (Clearwater), the addition of peat to gently lower the Ph is highly recommended (simulating the acidity of the tropical forest).

Compatibility and Tankmates: "Species Tank" jewel. Can be joined (at most) with Corydoras panda, Otocinclus, Paracheirodon innesi (Neon tetras). They will desperately flee from hyperkinetic fish like Danios.

Aquarium Reproduction: Challenge for experts. They lay few eggs in dense vegetation. Parents are not famous devourers of their eggs (like other Nannostomus), but the fry are so minute as to require weeks of paramecia.

Risks and Diseases: Water stress decay. The Espei has little tolerance for powerful filters. If forced to swim against the current to maintain position (which they hate), they will consume all their energy, rapidly falling ill with fungal infections.