Silver Hatchetfish

Geographic Origin and Biotope: Wide distribution in the central Amazon basins (Peru, Brazil) and the Guianas. Inhabits flooded woodland swamps, very slow-flowing trickles (Igarapè) covered by the forest canopy and filled with insects fallen into the water.

Taxonomy and Morphology: Silver Hatchetfish. It is the most iconic and available species of the genus. Identical to its cousin maculatus in the hyper-compressed half-moon shape and superior mouth, reaches about 6.5 cm (2.5 inches) maximum length.

Social Behavior: STRICTLY to be kept in schools (minimum 8-10). It would remain constantly hidden and extremely stressed if kept individually. They station at the surface of the water, motionless for hours waiting, united in a very tight school.

Coloration and Sexual Dimorphism: Pure silver livery, very shiny and reflective, lacking the black spotting typical of G. maculatus. A thin opaque golden/green horizontal stripe runs along the body. Mature females recognizable by the slightly more convex dorsal profile (full of eggs).

Aquarium Setup: Hermetically covered aquarium (thick glass, closing holes and slits) at least 80 cm (32 inches) long, to ensure escape space (skimming) on the surface. Essential large patches of Limnobium laevigata to modulate the light and prevent panic attacks.

Diet and Feeding: Ignores what falls beyond 2 cm in depth. Base of light flakes and small slow-release floating granules (0.5 mm). Must be fed with dry/live insects (drosophila, springtails) to provide the correct chitin intake necessary for the intestine.

Water Quality: Strong need for stability of values rather than extreme parameters. pH from 6.0 to 7.0, medium hardness (GH 2-15) and mild temperatures of 23-27°C (73-81°F). Amber water (tannins) drastically reduces stress and prevents skin bacterial infections.

Compatibility and Tankmates: Perfect pacifists; totally ignore bottom and mid-water fish. Excellent with Neons, Corydoras, Otocinclus, Discus and Apistogramma. NEVER insert with aggressive surface fish (large Killifish, aggressive Bettas, large Gouramis).

Aquarium Reproduction: Officially documented only a few times. Similar to that of other hatchetfish: stormy courtship with leaps out of the water, spawning among floating roots. The fry need tiny infusoria for the first week.

Risks and Diseases: In addition to the usual jumping out of the tank, these wild-imported fish are chronically affected by Ich (White spot) and often waste away from malnutrition if one persists in feeding them with tablets or flakes that sink too quickly.