How Many Marble Hatchetfish in a 125-Gallon Tank?
In a 125-gallon tank you can comfortably keep about 6–178 Marble Hatchetfish. As a schooling species, never keep fewer than 6.
Why
Stocking is driven by adult size and waste output, not just fish count. Marble Hatchetfish reaches about 1.4" with a light bioload, and needs 75–82°F water at pH 5.5–7. Always cycle the tank and test water before adding livestock.
| Adult size | 1.4" |
|---|---|
| Minimum tank | 15 gallons |
| Temperature | 75–82°F |
| pH | 5.5–7 |
| Temperament | Peaceful |
| Schooling | Yes — group of 6+ |
| Diet | Micropredator |
| Care level | Moderate |
| Origin | Amazon basin |
More fish for a 125-gallon tank → Marble Hatchetfish tankmates →