How Many Red Swordtail in a 20-Gallon Tank?
In a 20-gallon tank you can comfortably keep about too few for a proper school Red Swordtail. As a schooling species, never keep fewer than 3.
Why
Stocking is driven by adult size and waste output, not just fish count. Red Swordtail reaches about 5.5" with a heavy bioload, and needs 72–82°F water at pH 7–8.4. Always cycle the tank and test water before adding livestock.
| Adult size | 5.5" |
|---|---|
| Minimum tank | 20 gallons |
| Temperature | 72–82°F |
| pH | 7–8.4 |
| Temperament | Semi-aggressive |
| Schooling | Yes — group of 3+ |
| Diet | Omnivore |
| Care level | Easy |
| Origin | Mexico to Honduras (captive-bred) |