Fish Stocking Calculator

The 1 inch per gallon rule doesn't account for fish body mass (a 10" oscar has far more mass than ten 1" tetras), activity level, waste production, or territorial behavior. We use 1 inch per 2 gallons as a safer baseline, adjusted for filtration and plants.

Better filtration means more biological capacity to process fish waste. A canister filter or sump can handle 20-30% more bioload than a basic hang-on-back filter. Multiple filters or oversized filtration lets you stock more heavily.

Yes! Plants absorb ammonia and nitrates, provide oxygen, and create beneficial bacteria surface area. A heavily planted tank can safely hold 10-20% more fish than an unplanted one with the same filtration.

Always use adult size, not current size. A 1" juvenile oscar will grow to 12-14". Fish grow to their genetic potential if properly cared for - don't believe the myth that fish grow to their tank size.

Most schooling fish (tetras, rasboras, corydoras, barbs) need groups of at least 6 to feel secure and display natural behavior. Some species like rummy-nose tetras show better schooling in groups of 10+.

If already overstocked: increase water change frequency (2-3x weekly), add more filtration, add live plants, and monitor water parameters closely with a test kit. Long-term, consider rehoming fish or upgrading tank size.