Nannostomus minimus
Nannostomus minimus, or the pencilfish as it is called, is naturally found in the Essequibo River basin, which flows through Guyana, South America. The fish are found in small tributaries and marshy areas of the river, heavily overgrown with aquatic vegetation, with lots of snags on the bottom and a thick cushion of fallen tree leaves. The water in these areas is dark coloured due to humic acids and other chemicals released by organics decomposing on the bottom. This species is little known in aquaristics, but is sometimes found and imported under the name of its congener Nannostomus marilynae.
Nannostomus minimus is grey-brown in colour. A reddish spot is present on the abdomen. The same spots are present at the base of the dorsal and caudal plumage. A thick black stripe runs along the entire body. The fins are colorless and translucent. Adult males have a more contrasting coloration and are usually slimmer than females. The maximum size of fish reaches 2 cm.
Nannostomus minimus is peaceful, but not the ideal fish for the community in a shared aquarium, because it has a small size and timid character. These fish should ideally be kept in a species aquarium or together with miniature non-aggressive characids. To make the fish less fearful, it is advisable to immediately buy a flock of at least 10 fish.
An aquarium should have a capacity of at least 50 litres. Use dark, fine gravel as substrate. The entire aquarium should be densely planted with plants, including floating. The bottom can be placed snags and pre-dried oak leaves. As decomposition in the leaf litter will breed colonies of bacteria, which serve as good supplementary food for the fry.
Water parameters: temperature 22-28° C, hardness dH 1-9°, acidity pH 4,0-6,5. Requires filtration, aeration and a weekly change of ¼ of the aquarium water with fresh. Do not introduce fish into an aquarium that has not yet established biological equilibrium.
Their natural menus consist of tiny invertebrates. Under aquarium conditions Nannostomus minimus feed a variety of dry food, as well as small frozen and live bloodworms and artemia. The food is given twice a day.
Reproduction
Under suitable keeping conditions, Nannostomus minimus can spawn without special measures. However, in order to increase the number of surviving fry will require a spawning tank in which a pair of producers will need to be planted. Neither lighting nor filtration is required in the spawning tank.
The female lays eggs chaotically scattered among the leaves of plants. Immediately after spawning, the spawners should be set aside. The eggs incubate for about 48 hours. The hatched fry are very tiny and should be fed live dust and specialized dry food with a size of 5-50 microns. As the fry grow, the menu begins to expand by giving them artemia. The fry are fed 4-5 times a day.
