What size tank do threadfin rainbowfish need?
At least 15 gallons (57 liters) for a group of 6. The smallest standard tank that works is the 15 gallon. A bigger tank is always easier to keep stable. We give the size for an adult fish in a proper group, because the small fish in the shop will grow. Scientific name: Iriatherina werneri.
How many threadfin rainbowfish in each tank size?
This is how many each standard tank carries comfortably if threadfin rainbowfish are the only fish in it. Share the tank with other species and the number goes down.
| Tank | How many threadfin rainbowfish |
|---|---|
| 5 gallon | Too small |
| 10 gallon | Too small |
| 20 gallon long | up to 14 |
| 29 gallon | up to 20 |
| 40 gallon breeder | up to 28 |
| 55 gallon | up to 39 |
| 75 gallon | up to 53 |
| 125 gallon | 60 or more |
Check threadfin rainbowfish against your own tank and other fish
Good to know
- Keep at least 6. Alone or in twos and threes, threadfin rainbowfish hide, stop eating well, or pick on each other.
- Its long fins are a target. Avoid fin-nippers such as tiger barbs and serpae tetras.
Tank mates for threadfin rainbowfish
These animals like the same water, are a safe size, and have a temper that fits. It is a match on paper: always watch new tankmates for the first week.
- Cardinal tetra
- Glowlight tetra
- Black neon tetra
- Harlequin rasbora
- Rummy-nose tetra
- Lemon tetra
- Cherry barb
- Bronze corydoras
Poor matches
- Betta: Betta often attacks other fish with long, flowing fins, such as threadfin rainbowfish.
- Fancy goldfish: Goldfish do best with other fancy goldfish.
- Tiger barb: Tiger barb nips fins and threadfin rainbowfish has long fins. Avoid this pair.
- Oscar: Oscar is aggressive and will bully or kill peaceful fish such as threadfin rainbowfish.
Questions and answers
What size tank do threadfin rainbowfish need?
At least 15 gallons (57 liters) for a group of 6. The smallest standard tank that works is the 15 gallon. A bigger tank is always easier to keep stable.
How many threadfin rainbowfish should be kept together?
At least 6. Threadfin rainbowfish are social animals and only behave naturally in a group. More is better if the tank has room.
Can threadfin rainbowfish live in a 10 gallon tank?
No. Threadfin rainbowfish needs at least 15 gallons (57 liters).
What temperature do threadfin rainbowfish need?
73–84 °F (23–29 °C), with a pH of 6–7.8. In most homes that means a heater.
Can threadfin rainbowfish live with a betta?
It is not a good match. Betta often attacks other fish with long, flowing fins, such as threadfin rainbowfish.
More fish
- Upside-down catfish
- Boeseman's rainbowfish
- Dwarf neon rainbowfish
- Clown killifish
- Rainbow shark
- Red-tailed black shark
- All 81 species
Adult size, tank size and water ranges follow the mainstream care consensus (Seriously Fish species profiles and FishBase maximum lengths). Where sources differ we use the more cautious figure. Stocking numbers come from our stocking calculator.