Species group: Pencilfish
Other common names: Red Arc Pencilfish; Ruby Red Pencilfish
Scientific name: Nannostomus mortenthaleri
The Coral Red Pencilfish is native to slow moving, heavily vegetated streams and tributaries in the Rio Nanay basin in Peru, South America.
The Coral Red Pencilfish are arguably the most beautiful species of Pencilfish. Both the sexes are extremely colorful but the display of colors during breeding is incomparable. Interestingly, the male fish gets deceived by a mirror. They imagine that there is another fish opposite and start displaying a fight in the spirit of competition. The 'Arc' in its name is due to its elongated body and pointed snout. It is a brilliant, beautiful red in color. There are two broad horizontal black lines on its body. The lower part of the fish's body is not as bright, bordering on white. It has a beautiful red body color with two strong horizontal black lines, giving it a broadly striped appearance. The lower portion is paler and often white.
Coral Red Pencilfish are small and peaceful, and do well in a well-planted community tank which contains non-aggressive fish.
The male Red Arcs tend to show aggression towards each other but the fights generally do not involve serious damage. It is not safe to keep too many males together.
Coral Red Pencilfish require a densely planted aquarium. They swim in all areas of the tank.