Fish comparison
Lambchop Rasbora vs Harlequin Rasbora
How the Lambchop Rasbora and Harlequin Rasbora compare on care, size, water and temperament, and which fish suits your tank.
By Mike ElmiraUpdated
TL;DR, Lambchop Rasbora vs Harlequin Rasbora
The Lambchop Rasbora and the Harlequin Rasbora are close cousins, both in the Trigonostigma group, so at a glance they ask for a lot of the same things. Both are happy somewhere around 23 to 28 °C and pH 5.5 to 7, so a single tank can suit either one. The Harlequin Rasbora is the more forgiving of the two, which matters if this is an early tank, while the Lambchop Rasbora rewards a bit more attention. If tank space is tight, the Lambchop Rasbora needs less room to feel settled; give the Harlequin Rasbora 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
- Lambchop Rasbora23–28 °C
- Harlequin Rasbora22–28 °C
pH
- Lambchop Rasbora5.5–7
- Harlequin Rasbora5.5–7.5
Hardness
- Lambchop Rasbora1–10 dGH
- Harlequin Rasbora2–12 dGH
What to plan for
- Lambchop Rasbora schools, stock at least 8You've planned for 1 lambchop rasbora. Lambchop 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.
- 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 |  FishLambchop RasboraTrigonostigma espei |  FishHarlequin RasboraTrigonostigma heteromorpha |
|---|---|---|
| Category | Fish | Fish |
| Origin | Thailand and Cambodia | Thailand, Malaysia, Sumatra |
| Family | Cyprinidae | Cyprinidae |
| Temperature | 23–28 °C | 22–28 °C |
| pH | 5.5–7.0 | 5.5–7.5 |
| Hardness (dGH) | 1–10 | 2–12 |
| Flow rate | Low to Medium | Low to Medium |
| Min tank | 45 L | 60 L |
| Adult size | 3–3.5 cm | 4–5 cm |
| Difficulty | 2 / 5 | 1 / 5 |
| Lifespan | 4–6 yrs | 5–8 yrs |
| Diet | Omnivore | Omnivore |
| Water column | Mid | Mid |
| Schooling | Yes | Yes |
| Plant safe | Yes | Yes |
| Shrimp safe | Yes (with adults) | 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 Lambchop Rasbora and Harlequin Rasbora together?
Yes. Their temperature and pH ranges overlap around 23 to 28 °C and pH 5.5 to 7, 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 Lambchop Rasbora or the Harlequin Rasbora?
The Harlequin Rasbora is the easier of the two, closer to very easy, while the Lambchop Rasbora leans beginner-friendly.
Do Lambchop Rasbora and Harlequin Rasbora need the same water?
Close to it. Aim for 23 to 28 °C and pH 5.5 to 7 and you're in the shared sweet spot for both. Full ranges are in the table above.
What's the main difference between the Lambchop Rasbora and the Harlequin Rasbora?
Space. The Lambchop Rasbora wants about 45 litres minimum and the Harlequin Rasbora around 60, so tank size can settle it.