Dwarf Pencilfish

The Dwarf Pencilfish originally comes from Venezuela, Peru and Colombia, where it inhabits shady areas of freshwater rivers with little current and dense underwater and bank vegetation. It belongs to the family of slender tetras and is mostly a calm fish. The black vertical stripes and the bright red spots offer a nice contrast to the light, silvery base colouration, which makes it a pretty eye-catcher.

Care in the aquarium

In terms of care, Nannostomus marginatus can be classified as moderately difficult. The Dwarf Pencilfish should be kept in an aquarium with a minimum edge length of 60 cm and should be kept in a group of at least 10 animals so that it feels comfortable. In groups that are too small, it can be much more fearful and shy. Socializing with lively animals is not a good option, but bottom dwellers like armored catfish are very suitable. Care should be taken to ensure that the water is nitrate-free, light and soft.

Feeding

In its natural habitat, this Nannostomus feeds on small worms and crustaceans, insect larvae and approach food. In the aquarium, it is optimally fed with small amounts of live and frozen food, but will also accept fine dry food.

Sexual characteristics and breeding

The sexes are differentiated primarily based on the physique and the shape of the fins. While the somewhat fuller females have pointed anal fins, the males have these rounded and lined with black. For breeding, fine-leaved plants should be present in the tank, between which the females spawn. In order to increase the fish’s willingness to spawn, more live food is fed and the tank is darkened. The water should also be very soft, rather acidic and, above all, clean. After spawning, the eggs should be transferred to a separate breeding tank or the adults should be removed from the tank, since dwarf ornamental tetras are spawn predators and do not stop at their own offspring. After about 1-2 days, the dwarfs hatch and, after the yolk sac has been consumed, can be fed with infusoria, copepods and newly hatched Artemia nauplii. For healthy growth of the young fish, the water should be cooler.