Originally Posted by fishyinpa
oh okay thanks.
I dont think they were golden pencils,bc I looked at the pictures online. These ones were doing that oblong kinda swimming. i forget the real name,but one of the striped pencils.
If you mean swimming at an oblique angle, it is either Nannobrycon eques or N. unifasciatus. They are very similar in appearance, and the only two species in this genus. The former is more common in the hobby as it is now being commercially raised; the latter is very rare, and to my knowledge is always wild caught.
Whichever, they are nice fish, very sedate and quiet; they do well with quiet small fish, nothing active or they can become too frightened to eat. Both species occur in slow shallow streams with heavy streambank vegetation and roots and branches extending into the water, amongst which they swim. N. eques has a fairly extensive range through the Amazon basin, in the middle Amazon, various tributaries of the Rio Negro into Venezuela and Columbia, and the Guyanas.
They must be in groups (minimum 5 but more if space allows) or they will be continually stressed out and waste away. Floating plants are mandatory [Ceratopteris is perfect] as they provide shelter; these fish come from very overgrown shaded waters and are adverse to bright lighting. The fish spend their day cruising through dangling roots looking for bits of food. They will also continually graze plant leaves and wood, looking for any miniscule food particles. Once established in the aquarium they will readily accept prepared foods (flake, freeze-dried bloodworms and insects a particular favourite, and frozen bloodworms and daphnia). Sometimes it takes them a while to settle in before they will be comfortable enough to eat, so don't panic. If they seem reluctant to eat, try feeding them late in the evening just before or immediately after the tank light goes out (there must be light in the room of course) as in nature they feed mainly at dusk.
They have very small terminal mouths [terminal= directly at the end] which are always open. The genus name is Greek for "small biter". The species name "eques" is the latin for horse, and "unifasciatus" is latin for one striped. These fish have gone through a few name changes, originally in a genus named Poecilobrycon under which name they are still encountered in stores. In 1975 Weitzman & Cobb placed them in the genus Nannostomus, but in 1977 Gery determined that the two species should be in Nannobrycon due to several internal differences; the obvious fact that they swim at an oblique angle (and none of the other pencilfish do this) makes it easy for aquarists to tell them apart.
Photos of both species attached, N. eques upper photo, N. unifasciatus lower.