Anduzei's Nannostomus

About

Anduzei's Nannostomus (Nannostomus anduzei) holds the title of smallest member of its genus, topping out at just over half an inch as a fully grown adult. It comes from the blackwater rivers of South America, specifically the upper Orinoco basin and the Ereré River, a tributary of the Rio Negro, and it occasionally turns up in the hobby as an accidental inclusion in wild fish shipments out of Manaus rather than as a deliberately collected export. Males are easy to pick out by the intensely red coloration on the caudal peduncle and anal fin, and interestingly this species lacks the distinct night-pattern of spots or bars that most other pencilfish display, instead fading to a general paleness after dark. Behaviorally it is peaceful toward other fish but has a social dynamic within its own group that involves regular low-level sparring between males during the day, which can result in minor fin nipping. This is best managed by keeping a large group of ten or more, which distributes any tension and also brings out bolder, more natural behavior. Because of its tiny size it really should not share a tank with anything that could bully or outcompete it at feeding time. Kept with similarly small, gentle species it can thrive, and captive breeding, while uncommon, has been achieved in well-planted aquaria.