Why do I need more fingerlings than my target count?

Not all stocked fish survive to harvest. Typical survival rates are 70–90% depending on species, system, and management. You must stock more to compensate for expected mortality.

What is a typical survival rate?

In well-managed systems: tilapia 80–90%, salmon 75–85%, catfish 80–90%. Poor water quality or disease can drop survival below 50%.

How does fry size affect stocking?

Larger fingerlings generally have higher survival rates but cost more per unit. The optimal balance depends on fry cost vs. expected mortality at different sizes.

ToolsConductScience tool

AquacultureFree in-browser calculator

Stocking Requirement Calculator.

Calculate how many fingerlings to stock to reach your target harvest biomass, accounting for expected mortality.

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Stocking Parameters

Target Biomass at Harvest (kg)

Avg Fry/Fingerling Weight (g)

Expected Survival: 80%

10%50%75%100%

Results

Fingerlings Needed

2,500

to stock

Target Biomass

1,000 kg

at harvest

Stocking Weight

1250.0 kg

total fry weight

Survival

80%

expected

When to use

Pre-cycle stocking planning
Ordering fingerlings from hatcheries
Comparing stocking scenarios at different survival rates
Budget planning for fingerling costs

Do not use for

Without adjusting survival rate for your specific conditions — defaults are averages only

Survival varies by stage

Fry-to-fingerling survival (first 30 days) is much lower than fingerling-to-harvest. Use stage-appropriate survival estimates.

Density limits

Stocking more fish to compensate for mortality may exceed density limits. Always cross-check with stocking density guidelines.

Method

Fingerlings needed = target count at harvest / (survival% / 100). Target count = target biomass (kg) / individual weight (kg). Stocking weight = fingerlings $\times$ avg fry weight.

Published

Published 2026-04-08. Calculations support planning and documentation; verify procurement decisions against manufacturer specifications or institutional SOPs.

How to cite

How to Cite

ConductScience Stocking Requirement Calculator. ConductScience, Inc. 2026. Available at: https://conductscience.com/tools/fish-stocking-calculator

FAO. Aquaculture Feed and Fertilizer Resources Information System. 2020.

Stocking Calculations in Aquaculture

Stocking the correct number of fingerlings is critical for meeting production targets. Under-stocking wastes tank capacity; over-stocking wastes fingerling cost and may exceed density limits. The key variable is expected survival rate — which determines how many extra fish must be stocked to reach the target harvest count after accounting for mortality.

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