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Brown Pencilfish

Nannostomus eques

Freshwater South America

Fascinating for its characteristic habit of swimming obliquely at a forty-five-degree angle with snout tilted upwards. This gentle characin thrives under dim lighting amongst floating plant roots. Best maintained in a peaceful group with other tiny fishes, it easily feels intimidated by active tankmates.

Also called: Brown pencilfish, Diptail pencilfish, Tubemouth pencilfish, Tube-mouthed pencilfish.

4.5 cm adult length, drawn to scale. slim body.

Try it in the planner Opens a tank sized to its minimum with 6 fish added.

What it needs

ItemValueBecause
Adult length 4.5 cm Used for the Space check: the tank must be long enough for the fish to turn round.
Smallest tank 50 L, at least 50 cm long estimated The least water and floor length this species is kept in for good, as a single fish or smallest group.
Extra water per added fish 5 L estimated What each further fish adds once the minimum is met.
Waste load Class 1 of 5 estimated How much waste an adult makes against its size. Feeds the Load check.
Temperature 22 to 28 C Stock sharing a tank need overlapping ranges.
pH 5.5 to 7 Compared with tankmates in the Water check.
Hardness GH 2 to 8, KH 1 to 4 Degrees of general and carbonate hardness.
Flow Low Low-flow fish are stressed in a strong current.
Light Dim Matched to the lighting class on the needs sheet.
Group size At least 6, ideally 10 Kept alone or in small numbers it hides, fades or turns on tankmates.
Temperament Peaceful Not territorial.
Swims in Upper water Fish that use different levels share a tank more easily.
Lifespan About 4 years A fish is a long commitment.
Experience Suits a first tank A guide to how forgiving the species is of mistakes.
Jumps Yes Keep the tank covered.

Tags marked estimated are judged from the size and habits of the species rather than measured, so treat them as a sensible default.

Diet and tank layout

Brown Pencilfish is an micro feeder that swims in the upper water. It is safe with plants. Give it plenty of cover.

Tankmates

Works with

No close matches in the data. Check the pair tool.

Depends

Avoid

Compare any two fish on the compatibility page, or print the equipment for a stock on the needs sheet. How this is worked out: the method.