Threadfin Rainbowfish tank mates
Iriatherina werneri
5 rated pairings from the Threadfin Rainbowfish care guide. Compatibility here means water, temperament, tank zone and adult size all line up — the note on each card says why. Threadfin Rainbowfish needs at least 10 gallons on its own; every companion adds to that.
Excellent matches
2 · Same water, complementary zones, no conflict.
Emerald Dwarf Rasbora
Danio erythromicron
10 gal min · 1" adult · Peaceful
Similar size, peaceful temperament, and compatible water parameters make them ideal companions
Least Killifish
Heterandria formosa
5 gal min · 1.5" adult · Peaceful
Tiny, non-aggressive, and thrive in similar soft, slightly acidic conditions
Good matches
2 · Compatible with normal care — watch space and numbers.
Red Cherry Shrimp
Neocaridina davidi
5 gal min · 1.2" adult · Peaceful
Peaceful invertebrates that won't compete for micro foods and add biological balance
Otocinclus
Otocinclus vittatus
10 gal min · 1.5" adult · Peaceful
Small, gentle algae eaters that occupy different water zones and have compatible care needs
Use caution
1 · Works in the right setup; read the note before combining.Planning this tank?
Run the whole stock list through the calculator — it checks bioload and schooling numbers, not just pairings.