No photo yet
Sign in to submit the first photo
Harrison's Pencilfish
Nannostomus harrisoni
📍 South America
Harrison's Pencilfish is a small, slender South American fish known for its distinctive horizontal stripe and peaceful demeanor. These delicate fish are best kept in groups and thrive in heavily planted, dimly lit aquariums with soft, acidic water. They are excellent for planted tanks and community setups with other small, peaceful species.
Care Guide
Diet
Harrison's Pencilfish are micropredators that feed on small live foods such as infusoria, micro worms, and small crustaceans. Supplement with high-quality micro pellets and finely crushed flake food. Feed small amounts 2-3 times daily, offering only what they can consume in a few minutes.
Behavior
These fish are shy and peaceful, preferring to stay in loose groups among dense vegetation. They exhibit a distinctive horizontal stripe along their body and are most active during low-light conditions. They rarely venture into open water and spend most of their time near plants and substrate.
Breeding
Breeding is challenging in home aquariums and requires very soft, acidic water (pH 5.5-6.5) and dense vegetation. Eggs are scattered among plants and parents do not provide care. Fry are extremely small and require infusoria or liquid fry food for the first weeks.
Tank Mates
Similar size and peaceful temperament; both prefer soft, acidic water
Comparable water requirements and non-aggressive behavior
Small, peaceful bottom dweller that won't compete for food
Peaceful invertebrate that helps with algae control and won't harm pencilfish
Provides essential shelter and shade that pencilfish require
Common Diseases
Ich (Ichthyophthirius multifiliis)
White spots on body and fins, rapid breathing, lethargy, rubbing against objects
Increase temperature gradually to 28-30 C (82-86 F), use aquarium salt at half dose, perform daily water changes, add aeration
Fin Rot
Frayed or deteriorating fins, discoloration at fin edges, lethargy
Improve water quality with frequent water changes, reduce stocking density, treat with antibacterial medication if severe
Neon Tetra Disease (Pleistophora)
Loss of coloration, spinal curvature, lethargy, loss of appetite
No cure available; isolate affected fish to prevent spread, maintain pristine water conditions, remove deceased fish immediately
Malnutrition
Stunted growth, faded coloration, pinched belly, lethargy
Provide varied diet of live foods, quality micro pellets, and vegetable matter; feed multiple times daily in small portions
Community Photos
0 photosPhotos are added when members log a tank with this species and upload a photo in their tank journal. Add your own tank to contribute.
No photos yet — add a tank with Harrison's Pencilfish to be the first!
Sign in to vote.
Tips from the community 💡
0 tipsReal experiences, care advice, and keeper notes. Finn learns from these too.
Sign in to share your experience.
No community tips yet — be the first to share your knowledge!
Quick Facts
- diet
- Omnivore - small live foods, micro pellets, and vegetable matter
- lifespan
- 3-5 years
- max size
- 3.5 cm (1.4 in)
- tank size
- 10 gallons minimum
- temperament
- peaceful
Water it likes
- ph
- 5.5-7.0
- ammonia
- 0 ppm
- nitrate
- <20 ppm
- hardness
- 2-8 dGH
- temperature
- 72–79°F (22–26°C)