Fish comparison
Florida Flagfish vs Harlequin Rasbora
How the Florida Flagfish and Harlequin Rasbora compare on care, size, water and temperament, and which fish suits your tank.
By Mike ElmiraUpdated
TL;DR, Florida Flagfish vs Harlequin Rasbora
The Florida Flagfish 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 6.5 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 Florida Flagfish the nod when you have the litres to spare.
Group compatibility overview
Excellent fit
Every key parameter overlaps and no major conflicts surfaced.
1 note
Temperature
- Florida Flagfish18–26 °C
- Harlequin Rasbora22–28 °C
pH
- Florida Flagfish6.5–8
- Harlequin Rasbora5.5–7.5
Hardness
- Florida Flagfish5–20 dGH
- Harlequin Rasbora2–12 dGH
What to plan for
- 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.
Full attributes
Every parameter, side by side| Parameter |  FishFlorida FlagfishJordanella floridae |  FishHarlequin RasboraTrigonostigma heteromorpha |
|---|---|---|
| Category | Fish | Fish |
| Origin | Florida and the southeastern United States | Thailand, Malaysia, Sumatra |
| Family | Cyprinodontidae | Cyprinidae |
| Temperature | 18–26 °C | 22–28 °C |
| pH | 6.5–8.0 | 5.5–7.5 |
| Hardness (dGH) | 5–20 | 2–12 |
| Flow rate | Low to Medium | Low to Medium |
| Min tank | 75 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 (heavy algae grazer) | Omnivore |
| Water column | All | Mid |
| Schooling | Loose group | 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 Florida Flagfish and Harlequin Rasbora together?
Yes. Their temperature and pH ranges overlap around 22 to 26 °C and pH 6.5 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 Florida Flagfish 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 Florida Flagfish and Harlequin Rasbora need the same water?
Close to it. Aim for 22 to 26 °C and pH 6.5 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 Florida Flagfish and the Harlequin Rasbora?
Temperament is the big one. The Florida Flagfish is semi-aggressive and the Harlequin Rasbora is peaceful, which changes who you can house them with.