Greenstripe Pencilfish

About

The Greenstripe Pencilfish (Nannostomus marilynae) is a slim, small characid from the blackwater rivers of South America, collected from the Negro and Vichada river basins. It stays small even at maturity, topping out around two inches, and carries three distinct dark lateral stripes along its sides. One of the more interesting things about this species, and pencilfish in general, is its nighttime color shift: when the lights go out, those stripes give way to a vertically barred, camouflaged pattern. Research suggests this change is hardwired and happens even in blind individuals, so don't be alarmed when your fish looks completely different in the morning before the tank lights come on. In the aquarium, Greenstripe Pencilfish are best kept in groups of ten or more. Larger groups reduce any squabbling between individuals and bring out bolder, more natural behavior. They inhabit the middle to upper water column and pair really well as dither fish alongside Apistogramma and other dwarf cichlids. Avoid boisterous or fast-moving tankmates. These are gentle fish that won't compete well at feeding time. They do show up in the hobby occasionally, though more often as accidental bycatch in cardinal tetra shipments than as intentional imports, so snap them up when you find them. Breeding is possible in a mature, well-planted setup, though it takes some patience.