Fish comparison
Black Skirt Tetra vs Harlequin Rasbora
How the Black Skirt Tetra and Harlequin Rasbora compare on care, size, water and temperament, and which fish suits your tank.
By Mike ElmiraUpdated
TL;DR, Black Skirt Tetra vs Harlequin Rasbora
The Black Skirt Tetra and the Harlequin Rasbora come up together a lot when people are choosing a fish, and they are close enough to weigh side by side. Both are happy somewhere around 22 to 26 °C and pH 6 to 7.5, so a single tank can suit either one. Neither is harder than the other to keep, so the choice comes down to look and stocking rather than skill. If tank space is tight, the Harlequin Rasbora needs less room to feel settled; give the Black Skirt Tetra the nod when you have the litres to spare.
Group compatibility overview
Excellent fit
Every key parameter overlaps and no major conflicts surfaced.
4 notes
Temperature
- Black Skirt Tetra20–26 °C
- Harlequin Rasbora22–28 °C
pH
- Black Skirt Tetra6–7.5
- Harlequin Rasbora5.5–7.5
Hardness
- Black Skirt Tetra4–15 dGH
- Harlequin Rasbora2–12 dGH
What to plan for
- Black Skirt Tetra schools, stock at least 6You've planned for 1 black skirt tetra. Black Skirt Tetra need a group of at least 6 to feel safe and shoal naturally, below that they're stressed and lose colour. Dial up the count, or remove the species.
- Harlequin Rasbora schools, stock at least 8You've planned for 1 harlequin rasbora. Harlequin Rasbora need a group of at least 8 to feel safe and shoal naturally, below that they're stressed and lose colour. Dial up the count, or remove the species.
- No bottom teamNo bottom-dwelling fish or shrimp. A small group of corydoras or a shrimp colony picks up leftover food and keeps detritus in check.
- 100% of your fish swim in the midHeavy concentration in a single zone. Spreading stocking across all three levels makes the tank read fuller for the same bioload.
Full attributes
Every parameter, side by side| Parameter |  FishBlack Skirt TetraGymnocorymbus ternetzi |  FishHarlequin RasboraTrigonostigma heteromorpha |
|---|---|---|
| Category | Fish | Fish |
| Origin | Paraguay, southern Brazil, northern Argentina | Thailand, Malaysia, Sumatra |
| Family | Characidae | Cyprinidae |
| Temperature | 20–26 °C | 22–28 °C |
| pH | 6.0–7.5 | 5.5–7.5 |
| Hardness (dGH) | 4–15 | 2–12 |
| Flow rate | Low to Medium | Low to Medium |
| Min tank | 80 L | 60 L |
| Adult size | 5–6 cm | 4–5 cm |
| Difficulty | 1 / 5 | 1 / 5 |
| Lifespan | 3–5 yrs | 5–8 yrs |
| Diet | Omnivore | Omnivore |
| Water column | Mid | Mid |
| Schooling | Yes | Yes |
| Plant safe | Yes | Yes |
| Shrimp safe | Adults only | Mostly (may eat shrimplets) |
Frequently asked questions
Direct answers to the questions search engines and AI assistants surface most often about this species.
Can you keep Black Skirt Tetra and Harlequin Rasbora together?
Yes. Their temperature and pH ranges overlap around 22 to 26 °C and pH 6 to 7.5, so one set of water conditions keeps both comfortable. Match group sizes and cover the usual planted-tank basics and they share a tank fine.
Which is easier to keep, the Black Skirt Tetra or the Harlequin Rasbora?
They sit at the same care level, both very easy, so neither is the obvious beginner pick. The decision is really about the look you're after.
Do Black Skirt Tetra and Harlequin Rasbora need the same water?
Close to it. Aim for 22 to 26 °C and pH 6 to 7.5 and you're in the shared sweet spot for both. Full ranges are in the table above.
What's the main difference between the Black Skirt Tetra and the Harlequin Rasbora?
Space. The Black Skirt Tetra wants about 80 litres minimum and the Harlequin Rasbora around 60, so tank size can settle it.