Stocking density calculator
Stocking density is the number of animals placed per square metre of pond or per cubic metre of tank. Enter the unit size and the density you plan to stock at to get the number of fish or postlarvae to order, and add survival and a target harvest weight to see the biomass the unit will be carrying at the end of the cycle.
- Ponds per m², tanks per m³
- Fish and shrimp
- Harvest load, not just stocking count
- Runs in the browser, no sign-up
Calculate stocking
Water surface area. One hectare is 10,000 m². Working water volume of the tank or system.
The density you have decided to stock at. The density you have decided to stock at.
Adds the biomass going in.
Your own figure for this unit and species.
With survival, adds the load at harvest.
- Animals to stock
- - animals
- Biomass at stocking
- - kg
- Biomass at harvest
- - kg
- Load at harvest
- - kg/m²kg/m³
Calculations run in your browser. Nothing is sent or stored.
How is stocking density calculated?
Stocking density is the number of animals divided by the size of the unit: water surface in square metres for a pond, water volume in cubic metres for a tank or recirculating system. Planning runs the other way round: the unit size multiplied by the chosen density gives the number of animals to stock. A 5,000 m² pond stocked at 12 per square metre takes 60,000 animals.
Ponds are measured by area because oxygen exchange happens at the surface. Tanks and RAS are measured by volume because the water is managed as a volume, and there the figure that matters most is usually biomass per cubic metre rather than a head count.
The number that matters is the load at harvest
The stocking count describes day one. The limit a unit actually runs into is the biomass it carries near the end of the cycle, when the animals are at their heaviest and demand the most oxygen and feed. Survival multiplied by the stocking count gives the animals left at harvest, and multiplied by the harvest weight gives that final load in kilograms per square metre or cubic metre.
Two ponds stocked at the same density can end at very different loads if their survival differs, which is why the density decision is only as good as the survival figure behind it.
Why this page does not recommend a density
A safe density depends on the species, the system, the aeration, the water exchange and how intensively the unit is managed. A single recommended number published without that context would be wrong for most of the people reading it. The farm's own history, unit by unit, is the better guide: what each unit carried at harvest in past cycles, and how it performed at that load.
AquaOS tracks the biomass in every growing unit as the cycle runs and forecasts when each system crosses its capacity, so the harvest load is watched weeks ahead rather than discovered on the day.
Frequently asked questions
What is the difference between stocking density and biomass density?
Stocking density counts animals per unit of area or volume. Biomass density weighs them: kilograms per square metre or per cubic metre. Stocking density is set once at the start; biomass density rises every day the animals grow, and it is the figure that approaches the limit of the unit.
Should shrimp ponds be calculated per square metre or per hectare?
Both are used and they describe the same thing. Postlarvae per square metre is the common way to state density; hectares are common for pond area and for yield. One hectare is 10,000 square metres, so a density per square metre multiplied by 10,000 gives the count per hectare.
How do I account for mortality when planning density?
Stock at the planned density and apply your expected survival to project the animals left at harvest. Use a survival figure from this unit's own previous cycles where one exists, and revise the projection during the cycle as samplings and mortality records come in.
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