Dwarf Pencilfish (Nannostomus Marginatus) are somewhat a favourite of mine and I think they are very underrated.
Some of the things I like about Dwarf Pencilfish are:
- They are happy to live in a wide range of water parameters ie 22 to 28 °C and PH from 4 to 7.
- They are a peaceful fish and accepting water parameters across a wide range which makes them good tank mates in many situations.
- They occupy the top portion of the tank which can often be unoccupied or less populated in community tanks.
- Unique style and appearance, they are long and narrow with a silver and black stripes running the length of their body with some red highlights.
- They are small so it is easy to keep 8 or more in a group which will help them feel more secure and encourage their natural behaviour.
About Dwarf Pencilfish
Dwarf Pencilfish Profile
Origin: Guyana and Suriname and parts of the Amazon basin in Peru, Colombia, and Brazil.
Size: 2 to 2.5cm
Minimum tank size: 10 gallons (38 liters) depending on setup and tank mates.
Tank region: Upper region of the tank.
Water temperature: 72 - 82 °F (22 - 28 °C)
Water conditions: PH between 4 and 7. Soft water with a low TDS is preferred.
Difficulty to keep: Beginner to intermediate level
Dwarf Pencilfish Behaviour And Personality
Dwarf Pencilfish are a peaceful and somewhat shy fish which originate from a wide area including Guyana and Suriname and parts of the Amazon basin in Peru, Colombia, and Brazil.
They usually occupy slow moving almost still water which is typically fairly shallow, heavily planted and contain leaf litter.
They appreciate the company of their own species and usually swim in a loose shoal.
Dwarf Pencilfish Male vs Female
Male
Males are thinner compared to the females.
Female
Females are generally more thickset, rounder and stocky compared to the males.
Feeding Dwarf Pencilfish
In the wild Dwarf Pencilfish mainly feed on insects and other invertebrates at the surface of the water.
In our home aquariums they will accept live or frozen brine shrimp, microworms etc. Dry foods will also usually be accepted. Keep in mind that Dwarf Pencilfish have small mouths so any foods need to be suitably sized.
Slow sinking micro pellets which initially float are a suitable dry food.
Aquarium Setup For Dwarf Pencilfish
As Dwarf Pencilfish can be shy it is important to setup the aquarium so that the fish feel safe and comfortable. I suggest including the following:
Plants
They appreciate heavily planted environments. So ensure at least some plants are present in the aquarium, the more the merrier!
Also consider floating plants which will reduce light and proved some added cover.
Driftwood
Adding driftwood which provides areas of cover and breaks in line of sight is also beneficial and mimics their natural habitat.
Leaf litter
Leaf litter is commonly found in the slow moving shallow waters which Dwarf Pencilfish occupy in the wild. Consider adding some leaf litter such as dried almond leaves to your aquarium.
Filtration
All aquariums require an established filter to maintain water quality for the fish. In the case of Dwarf Pencilfish which inhabit slow moving or even still water it is recommended to have gentle filtration. Air driven sponge filters are a good low cost option.
Heater
Depending on your climate and where your aquarium in located a aquarium heater will likely be required. Choose a reputable brand with a wattage to suit the size of your aquarium.
Dwarf Pencilfish Tank Mates
Dwarf Pencilfish are best kept with other small non-aggressive fish such as Tetras or Corydoras Catfish.
Dwarf Pencilfish are also fantastic tank mates for Apsitogramma and other dwarf cichlids since they occupy the upper regions of the tank, leaving the bottom half of the tank available to the dwarf cichlids.
Conclusion
Dwarf Pencilfish (Nannostomus Marginatus) are a underrated fish with unique colors and characteristics.
They occupy the top region of the aquarium and can be a great addition to community tanks.
