Harlequin Rasbora: Tank Size, Tank Mates and Setup
A calm, hardy schooling fish with a black triangle patch. Keep six or more.
- Minimum tank
- 10 gallons
- Temperature
- 73–82°F
- Group size
- 6 or more
- Adult size
- 2 inMiddle of the tank
- One of the most reliable schooling fish for a first community tank.
Trigonostigma heteromorpha. Figures are commonly published care ranges; see how it works.
How many harlequin rasboras per tank size
The most you could keep if harlequin rasboras were the only species. Open a size in the builder to add tank mates.
| Tank | Harlequin rasbora, kept alone | |
|---|---|---|
| 5 gallon | Too small (needs 10+ gal) | |
| 10 gallon | Up to 6 | Plan this tank |
| 20 gallon | Up to 14 | Plan this tank |
| 29 gallon | Up to 23 | Plan this tank |
| 40 gallon | Up to 32 | Plan this tank |
| 55 gallon | Up to 44 | Plan this tank |
| 75 gallon | Up to 61 | Plan this tank |
What you need for harlequin rasboras in a 10-gallon tank
A starting setup: 6 harlequin rasboras in the smallest standard tank that suits them.
10-gallon tank
- These fit a 10-gallon tank and get along. Aim for about 78°F.
Equipment, sized for this tank
Starter supplies
Paid links. As an Amazon Associate, TankStarter earns from qualifying purchases. Sizes are estimates from published care guidelines, not hands-on testing.
Harlequin rasbora tank mates
These share a temperature range and temperament with harlequin rasboras, with no warnings from our checks.
Use caution with: white cloud minnow, fancy goldfish. Add them in the builder to see why.
Plan a tank around harlequin rasboras
Add tank mates, check the stocking level and get the equipment sized for your tank.
Open the tank builderHarlequin rasbora questions
What size tank does a harlequin rasbora need?
At least 10 gallons for a group of 6. A larger tank is more stable and gives you more choice of tank mates.
How many harlequin rasboras can I keep in a 10-gallon tank?
Up to about 6 if they are the only species in the tank. Fewer if you add other fish.
Do harlequin rasboras need a heater?
Usually yes. Harlequin rasbora does best at 73–82°F, which is warmer than most rooms. A 10-gallon tank needs about 50 watts in a 68°F room.
What fish can live with harlequin rasboras?
Good matches include bettas, neon tetras, cardinal tetras, ember tetras, rummy-nose tetras, black skirt tetras. They share a temperature range and temperament with harlequin rasboras.