Three-lined Pencilfish tank mates
Nannostomus trifasciatus
6 rated pairings from the Three-lined Pencilfish care guide. Compatibility here means water, temperament, tank zone and adult size all line up — the note on each card says why. Three-lined Pencilfish needs at least 15 gallons on its own; every companion adds to that.
Excellent matches
5 · Same water, complementary zones, no conflict.
Otocinclus
Otocinclus vittatus
10 gal min · 1.5" adult · Peaceful
Similar size, peaceful temperament, and preference for low-flow planted tanks make them ideal companions
Neon Tetra
Paracheirodon innesi
10 gal min · 1.5" adult · Peaceful
Compatible water parameters, peaceful schooling behavior, and similar size create a harmonious community
Cardinal Tetra
Paracheirodon axelrodi
15 gal min · 2" adult · Peaceful
Shares preference for soft, acidic water and peaceful community setup; similar mid-water swimming zone
Dwarf Hairgrass
Eleocharis parvula
Essential foreground plant that provides shelter, spawning substrate, and creates the low-flow planted environment they prefer
Java Moss
Taxiphyllum barbieri
Dense moss provides hiding places, reduces stress in groups, and creates natural habitat similar to their native environment
Good matches
1 · Compatible with normal care — watch space and numbers.
Planning this tank?
Run the whole stock list through the calculator — it checks bioload and schooling numbers, not just pairings.