Should I buy it?
Brown / hockey-stick pencilfish
Nannostomus eques
Also known as: brown pencilfish, hockey-stick pencilfish, dwarf penguin (trade, not a penguin tetra)
A 5 cm torpedo pencilfish that prefers blackwater soft conditions. Peaceful and shrimp-safe. Needs tannins and soft water for full lateral colouring.
Brown / hockey-stick pencilfish tank mates · 100L tank size hub
peaceful · intermediate care
Sources & confidencehigh · partially verified · beginner: caution
Checked against several solid care sources that mostly agree. Numbers here are a careful starting point. Your tap water, tank size, and habits decide the rest. How we evaluate.
Best for: Blackwater planted tanks 100L or more at pH 5.5–7.0 with a school of six and small peaceful companions.
Avoid if: Hard alkaline tap water, active boisterous tank mates, or tanks above 28 °C.
Common mistakeKeeping brown pencilfish in standard hard tropical community water is how keepers invent faded 'hockey sticks' with no red line left. They want soft, acidic, tannin-stained conditions and micro-foods. A bright hard-water community flake tank is the wrong ownership plan.
Top things that go wrong
- Mouth gap vs tiny tank mates. May eat tank mates small enough to fit the adult mouth — plan adult sizes, not shop sizes.
- Group welfare — not a solo display fish. Plan at least **6** together for normal behaviour; smaller groups often mean stress, colour loss, or nipping depending on species.
- Shrimp & snails. Not shrimp-safe — adults, fry, or both get eaten.
What most shops don't tell you
- 1.Myth: brown pencilfish are hardy community flake fish for any planted community tank. Reality: they need soft acidic water, tannins, micro-foods, and a real school — hard bright community kits wash out the red line and starve shy fish quickly.
- 2.Predation risk scales with gape, night feeding, and crowding. 'they grew up together' is a schedule, not a law.
- 3.Classed peaceful for similar-sized community use. Still a bite-sized risk toward fry or very small comm fish in small volumes.
- 4.Housed in bright bare water. The fish hide all day and feed poorly.
- 5.Single specimens bought as a 'cure for ich' instead of starting with a real school of six or more.
- 6.Soft blackwater is not mandatory, but long-term hard alkaline water wastes the colour over months. Give them a long planted run to lead with the snout, not a cube.
About this species
Brown pencilfish are slender Amazon fish that hold a head-up, tail-down posture under cover. Soft, dim, acidic planted water in a real school is how the colour and the angle hold up.
- Black ruby barb100L min · same group, comparable tank size
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- Gold / Chinese barb120L min · same group, comparable tank size
- Golden / Beckford's pencilfish80L min · same group, comparable tank size
- Odessa Barb120L min · same group, comparable tank size
- Pearl Danio80L min · same group, comparable tank size
- Cherry Barb60L min · same group, similar adult size
- Dwarf pencilfish60L min · same group, similar adult size
- Adolfoi coryalso intermediate peaceful, similar tank size
- African freshwater butterflyfishalso intermediate peaceful, similar tank size
- Bamboo Shrimpalso intermediate peaceful, similar tank size
- Black ruby barbalso intermediate peaceful, similar tank size
- Boesemani Rainbowfishalso intermediate peaceful, similar tank size
- Bolivian Ramalso intermediate peaceful, similar tank size
No reverse lookups listed yet.
Plan grid
Key limits are above. Here: pH band, swim level, bioload, and activity.
Swim zones
Care snapshot
Quick compare before you buy. Not a score of how “good” the fish is.
- Beginner ease38
- Peacefulness76
- Community fit69
- Small-tank fit100
- Hardiness54
- Energy24
Numbers are deterministic planning indices from Fishori fields — not a scientific score of your individual fish.
Example setups
Starting points only. Run the pair checker for every fish you add.
Rough 100L+ layout: one calm centrepiece, 8–12 small tetras/rasboras, 6–8 corydoras-type bottom fish — verify every name in the pair checker before buying.
Safer directions include: Dwarf Gourami, Ember Tetra, Harlequin Rasbora.
Prioritise 6+ of Brown / hockey-stick pencilfish in 100L+ with filtration sized for messy feeding — add only mates that already pass pair checks with this species.
Compatibility
Tank mates for Brown / hockey-stick pencilfish
Usually safer (engine GOOD): Dwarf Gourami, Ember Tetra, Harlequin Rasbora. Conditional (CAUTION — read the pair page before buying): Angelfish, Betta, Corydoras Catfish, German Blue Ram, Neon Tetra. Avoid (RISKY): African Cichlid, Jack Dempsey, Oscar. Every name links to a live pair check — the lists are a shortlist, not a stocking plan.
Usually safer
Open a pair page with this fish as the starting point.
Needs planning
Read the blocking rule on each pair page before experimenting.
Usually avoid
Do-not-stock combinations on conservative hobby rules.
Compare with
Run a real pair check: Brown / hockey-stick pencilfish + Dwarf Gourami
Behaviour and temperament
Brown pencilfish are peaceful schoolers that stay calmer in groups of six or more in soft water. They are not fin-nippers. Stress shows as fading lines and surface-edge hiding when chemistry is wrong or food never arrives at their level.
What sets them off
- Sudden crowding
- Poor water quality
Fin nipping: Not a habitual fin-nipper; stressed or crowded individuals can still test fins.
Predation: May eat tank mates small enough to fit the adult mouth — plan adult sizes, not shop sizes.
Territory: Not strongly territorial, but still needs room so its working space does not overlap the next fish.
Planted tanks: excellent — easy plant ideas
In the glass: typical and warning signs
- Six or more hold mid-to-upper water among plants in soft tannin-stained tanks.
- Angled 'hockey stick' posture at rest is normal for the species.
- Faded red lines in hard alkaline water usually mean chemistry first.
- Thin fish after adding frantic top feeders mean competition failed.
- Low listed malice toward similar nano fish.
- They lose feeding contests long before they bully anyone else.
- Fix water and food size before rehoming 'failing' pencils.
- Remove frantic surface competitors at the first weight-loss week.
Fish behaviour can vary between individuals and tank setups. Always observe new fish closely after introduction.
Water, food, and grouping
Hardness
soft
Diet
carnivore
Brown pencilfish are surface-leaning carnivores that need micro-foods at the right level in soft, tannin-stained water. Fine frozen foods and tiny pellets keep condition; standard community flake races past them. Feed a school of six or more among plants, and expect the red line to fade if chemistry goes hard and bright.
Shrimp & snails
Not shrimp-safe — adults, fry, or both get eaten.
Schooling species — buy 6+ together. Smaller groups stress and lose colour.
- Hold 24 to 28 °C steadily on a real thermometer, not the dial on the heater.
- Aim for pH 5 to 7 and a hardness you can re-test in two weeks. A one-time strip in the shop car park is not a water test.
- Schooling species. Buy 6 or more from the same tank on the same day before adding any centrepiece fish.
- Tank volume meets or exceeds 100L published minimum for adults.
- You can stock at least 6 individuals (group welfare).
- Heater can hold 24–28°C without cooking cooler-water tank mates.
- No known fin-nippers paired with long-finned fish unless you accept documented risk.
- No tank mates small enough to fit the adult mouth gap for this species.
Explore and stocking hubs
Tank-mates hub, matching guides, category peers, and litre stocking lists around this species’ minimum tank.
Plan with tools
Check mates as pairs first, then add this fish in the tank builder for the full stocking.
Filtration & heating
A 100L minimum tank needs a filter rated for at least 400L/hr turnover and a heater to hold 24–28°C reliably.
Plant suggestions
Brown / hockey-stick pencilfish does well in planted tanks. Plants compatible with 24–28°C and pH 5–7:
Research: partially verified · Confidence: high · 3 linked source(s). We do not invent citations.
How Fishori evaluates compatibility (same logic as pair and tank tools).
- Seriously Fish. Nannostomus eques
Primary: aquarium size, water chemistry, behaviour, and compatibility (URL verified in upgrade script; recheck if site content changes).
- FishBase. Nannostomus eques
Secondary: taxonomy, distribution, and maximum length in nature; cross-check with aquarium import lines and measured tank parameters.
- Wikipedia. Nannostomus eques
Secondary: general species context; verify all husbandry numbers against a dedicated aquarium care sheet and your test kit, not a single table row.
Evidence notes
- The Seriously Fish profile for the binomial in this record was successfully reached as the primary aquarium reference.
- FishBase contributes natural-range size and habitat context. Translate those numbers through your heater, your water report, and your tank footprint before stocking.
- Wikipedia is only cited if the article URL returned OK. Use it for orientation, not as the only care sheet for an import.
- All compatibility text reflects typical hobby experience and the Fishori model. Individual fish, shop stress, and the order tank mates are added in can still defy a single-paragraph label.
Common questions about Brown / hockey-stick pencilfish
- How big do Brown / hockey-stick pencilfish get?
- Brown / hockey-stick pencilfish adults reach about 5 cm. Shop fish look smaller; stock for the adult length.
- What size tank does Brown / hockey-stick pencilfish need?
- 100L is the planning floor for adult swimming space and bioload. A 122L+ tank is the more comfortable long-term footprint. Length and depth matter as much as raw litres for active or territorial fish.
- Are Brown / hockey-stick pencilfish aggressive?
- Brown pencilfish are peaceful schoolers that stay calmer in groups of six or more in soft water. They are not fin-nippers. Stress shows as fading lines and surface-edge hiding when chemistry is wrong or food never arrives at their level.
- Do Brown / hockey-stick pencilfish need to be kept in a group?
- Schooling species — buy 6+ together. Smaller groups stress and lose colour.
- What is the most common mistake with Brown / hockey-stick pencilfish?
- Keeping brown pencilfish in standard hard tropical community water is how keepers invent faded 'hockey sticks' with no red line left. They want soft, acidic, tannin-stained conditions and micro-foods. A bright hard-water community flake tank is the wrong ownership plan.
- What fish can live with Brown / hockey-stick pencilfish?
- The Brown / hockey-stick pencilfish profile lists Dwarf Gourami, Ember Tetra, Harlequin Rasbora among its safer pairings (engine-checked GOOD). Angelfish, Betta, Corydoras Catfish, German Blue Ram are conditional (CAUTION): workable only with the specific conditions on each pair page. Avoid African Cichlid, Jack Dempsey, Oscar (RISKY). Run the pair checker for your exact water and tank size before stocking.