How Many Least Killifish in a 20-Gallon Tank?
In a 20-gallon tank you can comfortably keep about 3–55 Least Killifish. As a schooling species, never keep fewer than 3.
Why
Stocking is driven by adult size and waste output, not just fish count. Least Killifish reaches about 1.2" with a light bioload, and needs 66–79°F water at pH 7–8. Always cycle the tank and test water before adding livestock.
| Adult size | 1.2" |
|---|---|
| Minimum tank | 5 gallons |
| Temperature | 66–79°F |
| pH | 7–8 |
| Temperament | Peaceful |
| Schooling | Yes — group of 3+ |
| Diet | Omnivore |
| Care level | Easy |
| Origin | Southeastern United States |
More fish for a 20-gallon tank → Least Killifish tankmates →