Nannostomus beckfordi is a timid fish that is found in Guyana, the lower Rio Negro, and the central Amazon. They are a freshwater fish found in schools that will hide for most of the day if given the chance. For this reason they should be kept in schools in aquariums rather than alone. The males are generally smaller with more color and white tips on the end of their fins. Females are usually larger with less coloration and a larger abdominal region than the males. They can grow to a size of about two and one half inches long. They should be kept in a temperature around 75 - 79 degrees Fahrenheit with a pH of 6.0 - 7.5 and a hardness around 20 ppm, but they are not intolerant of other types of water.
I kept these fish in a ten gallon tank with plants from wall to wall. This was done with hair grass and Java Moss so when the parents spawn they will not be able to find and eat the eggs. I kept four males and four females together in the tank. They can be fed a variety of foods, but I have found they do better with live baby brineshrimp, white worms, or other sorts of live foods. They can and will eat flake food if offered though. I, instead of what the books said mention earlier, kept them with a pH around 7.2 - 7.4, a hardness of 0ppm, and temperature around 73 - 75 degrees Fahrenheit.
I never figured out when these fish spawned. I think it was a little from each female each day. Anyways, one day I was going along with the lights out in my room looking at my fish with a flashlight. When I got to the pencil fish tank a bunch of little lines with eyes started to come to the light. I immediately took the parents out of the tank and started to look with the light out some more. The same thing happened again, more little hairs with eyes started coming at the light from all over the tank. Then I started to dig around in my room and I got a shell light out. It was designed to go on the top of a gallon jar, but I used it to attract the baby fish. It worked perfect and even more little fish started to come to the light. I think they came to the light as an instinct of nature, they were looking for food. I figured out that all the little micro organisms growing in the tank came to the light and the little fish were eating them. So that was their first food, their next food was micro worms I put in the tank. This was after about one or two weeks after I found them. After about three weeks I started to feed them live baby birneshrimp, and finally after about one month I started to feed them a mixture of the baby brineshrimp and small amounts of fine crushed flake food.
These were a great fish to spawn. They are probably the easiest difficult species on our BAP program's list, but still a challenge. I would recommend them to breeders or people who just want a nice community fish. They were a fun, and unusual fish.