Purple Pencilfish – Nannostomus rubrocaudatus
The Purple Pencilfish (Nannostomus rubrocaudatus) is a stunning nano freshwater fish known for its purple-red body, horizontal stripe, vivid red tail, and peaceful schooling behavior. This colorful pencilfish is a favorite for planted aquariums, nano tanks, and natural aquascapes.
Native to Peru, Purple Pencilfish do best in stable, well-maintained aquariums with clean water, live plants, and calm tankmates. Their rich coloration stands out beautifully against green plants, driftwood, leaf litter, darker backgrounds, and blackwater-style setups.
Key Features
- Colorful purple-red body with vivid red tail
- Peaceful nano schooling fish
- Great for planted aquariums and aquascapes
- Best kept in groups of 8 or more
- Ideal for soft-water and blackwater-style setups
- Beautiful contrast against live plants and dark substrate
Care Guide
- Scientific Name: Nannostomus rubrocaudatus
- Common Name: Purple Pencilfish
- Origin: Peru
- Care Level: Moderate
- Temperament: Peaceful schooling fish
- Adult Size: Approximately 1.5–2 inches
- Minimum Tank Size: 15 gallons or larger recommended
- Water Temperature: 74–80°F
- pH Range: 5.5–7.0
- Hardness: Soft water preferred
- Diet: Omnivore
- Lifespan: Approximately 3–5 years with proper care
Why Choose Purple Pencilfish?
Purple Pencilfish are prized for their vibrant coloration, elegant body shape, and peaceful activity. Their purple-red tones and red tail make them stand out from many common schooling fish while still keeping a calm, natural appearance.
They are an excellent choice for aquarists who enjoy planted aquariums, nano fish, and refined aquascapes. A properly sized group helps reduce stress and brings out their best color, confidence, and natural behavior.
Ideal Tank Setup
Purple Pencilfish do best in a mature, stable aquarium with live plants, driftwood, floating plants, and gentle filtration. They prefer clean, soft, slightly acidic water, but stability is more important than chasing exact numbers.
Dark substrate, botanicals, leaf litter, and shaded areas can help create a comfortable natural environment while enhancing their red and purple coloration. Avoid strong flow or aggressive tankmates that may stress or outcompete them.
Compatible Tankmates
- Small peaceful tetras
- Small rasboras
- Other peaceful pencilfish
- Pygmy Corydoras
- Otocinclus
- Peaceful nano fish
- Dwarf shrimp with proper cover
- Small peaceful snails
Tankmates to Avoid
- Large or aggressive fish
- Fast, boisterous species that outcompete them for food
- Fin-nipping fish
- Predatory fish
- Fish that require hard, alkaline water
Diet & Feeding
Purple Pencilfish have small mouths and should be offered small, appropriately sized foods. Feed quality micro pellets, fine flakes, crushed flakes, frozen baby brine shrimp, daphnia, cyclops, and small live foods when available.
A varied diet helps support healthy color, activity, and overall condition. Feed small portions that the group can consume quickly.
Care Tips
- Keep in groups of 8 or more
- Use a mature, stable aquarium
- Provide live plants, floating plants, and gentle cover
- Maintain soft, clean, stable water when possible
- Feed small foods suited for nano fish
- Avoid aggressive or overly active tankmates
Frequently Asked Questions
Are Purple Pencilfish good for planted aquariums?
Yes. Purple Pencilfish are excellent for planted aquariums and aquascapes, where their purple-red coloration stands out against green plants and dark backgrounds.
How many Purple Pencilfish should I keep together?
Keep them in groups of at least 8 or more for best behavior, confidence, and reduced stress.
Do Purple Pencilfish require soft water?
They prefer soft, slightly acidic water, but they can adapt to stable neutral conditions when properly acclimated.
Can Purple Pencilfish be kept alone?
No. They are social schooling fish and should be kept in groups for long-term health and natural behavior.
How big do Purple Pencilfish get?
They typically reach approximately 1.5–2 inches as adults.
What do Purple Pencilfish eat?
They eat micro pellets, fine flakes, frozen baby brine shrimp, daphnia, cyclops, and other small foods.
Are these fish available for shipping?
No. Live fish are available for in-store purchase or local pickup only at Tropical Treasures Wyo in Cheyenne, Wyoming.
Available at Tropical Treasures Wyo
Purple Pencilfish are colorful peaceful nano fish for planted aquariums, blackwater-style setups, and calm freshwater community tanks. Visit Tropical Treasures Wyo in Cheyenne, Wyoming, to shop pencilfish, nano fish, freshwater fish, shrimp, snails, live aquarium plants, fish food, filtration supplies, and aquarium care products. Live livestock is available for in-store purchase or local pickup only.
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