Peruvian Red Pencilfish (Type II)
Nannostomus mortenthaleri

Care Level




Reef Compatible


Plant Safe


Max Size

Less than 2"

Minimum Tank Size

20 gallon


Black, Purple, Red, White



Water Conditions

Slightly Acidic (6.5-7.5 pH), Soft Water Hardness (3-5 dKH), and 68-76 degrees Fahrenheit


General: The Peruvian Red Pencilfish (Nannostomus mortenthaleri) naturally occupy various wetland ecosystems through-out Brazil. They typically have a lifespan of up to five years, reaching a length of up to two inches. The Peruvian Red Pencilfish should be kept in a tank size of twenty gallons, or larger. The larger the livingspace, the more likely the Pencilfish are to vibrantly display their true colors. Pencilfish are social, active, and willing to brighten up any planted aquarium.

Fecundity (Reproduction): The female Peruvian Red Pencilfish (Nannostomus mortenthaleri) will produce 20 to 30 eggs per clutch. Pre-feeding high a quality food during the period before actual egg dispersal can increase fecundity, as well as promote health of eggs.

Aquarium Diet (Omnivore): Spirulina, Brine Shrimp, Baby Brine Shrimp, Blackworms, Daphnia, Bloodworms, and Tropical Flake

Dimorphism: The male mortenthaleri Pencilfish will laterally produce a deep red color and have a white patch on the anterior end of the dorsal fin. The male will also turn a darker red, or even purple, when ready to reproduce. The female will be significantly less red in coloration, and be thick-bodied in comparison to the male.

Peruvian Red Pencilfish (Type II) Photo Gallery