Threadfin Rainbowfish

Threadfin Rainbowfish

Iriatherina werneri

Also known as: Featherfin Rainbow

💧 Freshwater ✌️ Peaceful 🟡 Moderate 🍽️ Omnivore Schooling (6+)

Delicate, ethereal rainbowfish with thread-like fin extensions. Males display to each other constantly.

Tank Size

15 gal
minimum (20+ preferred)

Temperature

75–82°F
24–28°C

pH Range

6–7.5
water acidity

Max Size

1.5"
3.8 cm

Lifespan

3–5 years
typical in captivity

Swim Level

Middle
preferred zone

Care Notes

Peaceful but delicate. Keep with gentle tank mates that won't outcompete for food or nip fins.

Feeding

Small frozen foods, micro pellets. Needs small food — has a tiny mouth.

Compatible Tank Mates

Neon Tetra 1.5" Cardinal Tetra 2" Rummy Nose Tetra 2" Ember Tetra 0.8" Congo Tetra 3.5" Glowlight Tetra 1.5" Harlequin Rasbora 2" Chili Rasbora 0.7" Zebra Danio 2" Bloodfin Tetra 2" Lemon Tetra 1.5" Black Neon Tetra 1.5"

Use Caution With

Celestial Pearl Danio 1" Giant Danio 4" Cockatoo Dwarf Cichlid 3" Firemouth Cichlid 6" Electric Blue Acara 6" Kribensis 4" Blue Acara 6" Rainbow Cichlid 5" Geophagus Tapajos Red Head 7" Festivum Cichlid 6" Agassiz's Dwarf Cichlid 3" Cupid Cichlid 5"

Incompatible With

Black Skirt Tetra 2.5" Serpae Tetra 1.75" White Cloud Mountain Minnow 1.5" Buenos Aires Tetra 3" Silvertip Tetra 2" Colombian Tetra 2.5" Blue Tetra 2.5" Long-Finned Serpae Tetra 1.8" Angelfish 6" Oscar 14" Discus 8" Jack Dempsey 10"

Check Compatibility

Want to check if Threadfin Rainbowfish is compatible with a specific fish? Use our compatibility checker to build your complete tank.