Hasemania nana, Reinhardt i. Lütken, 1874
Origin:Rio San Francisco and Rio Purus systems, Brazil. Hoedeman reports Rio Iguassu in Brazil.
Etymology: nanus L.: dwarf.
Synonyms: Hemigrammus nanus, Hasemania marginata, Hasemania melanura.
First European import: Germany, 1937, by H. Röse.
Description: See picture. Variable species.
Care: Easy to care for peaceful fish, which is very suitable for the community tank. They should be kept in small schools, in tanks that have adequate filtration. They need free swimming space, and places to hide like plantgroups. A bit of sunlight in the morning will show the fish in their best colors.
Temperature: 22-28 degrees.
Feeding:Omnivorous, all (small)food they can master.
Size: Up to 5 cm.
Breeding: A small tank(10 liters or more), a bit higher temperatures(24-25) and slightly acidic water will get the fish to spawn. Waterhardness below 10 dGH, and a substrate that will protest the eggs is necessary if you plan to raise large numbers of fry. This since the fish are avid eggeaters, which will eat the eggs even while spawning, and spawning is done over a period of time. The eggs will hatch in 36 hours, and the dark brown fry are extremely small, and really hard to spot. The fry will be free swimming 5-6 days later, and should be fed with infusoria.
Sexual dimorphism:Male has brighter colors than the female.
Additional: The origin reported by Baensch and Riehl is a bit strange, Rio Purus is in west Brazil, and Rio San Francisco is in east Brazil. This combined with the remark that it's a variable species could mean that research may lead to the conclusion that the fish are in fact different (sub)species.
Picture references:Pictures: E. Naus.
References:Baensch, H. A., Riehl, R.(1982): Aquarien Atlas I. Mergus Verlag, Melle, Germany.
Pinter, H.(1966): Handbuch der Aquarienfischzucht. Alfred Kernen Verlag, Stuttgart, Germany.
Hoedeman, J. J.(1969): Aquariumvissen encyclopedie 3. Elsevier Nederland B. V., Amsterdam, The Netherlands.
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