Calculator methodology, assumptions and limitations

Convert pond, raceway or tank dimensions into working water volume and surface area.

Formula

• volume_m3 = length_m × width_m × average_depth_m
• usable_volume_m3 = volume_m3 × 0.90 (allowance for 2:1 sloped bunds)
• surface_m2 = length_m × width_m; acres = surface_m2 ÷ 4046.86
• Imperial input is converted at 1 ft = 0.3048 m before any calculation.

Engineering assumptions

• Rectangular geometry with uniform average depth.
• The 10% bund deduction is a planning allowance, not a survey result.

Limitations

• Irregular, circular or terraced ponds are not modelled — use the circular formula in the notes.
• Does not account for freeboard, sediment build-up or seasonal drawdown.

Must be confirmed

• As-built survey volume
• Freeboard and embankment design

Convert circular or rectangular tank dimensions into water volume at working depth.

Formula

• Circular: volume_m3 = π × (diameter_m ÷ 2)² × water_depth_m
• Rectangular: volume_m3 = length × width × water_depth

Engineering assumptions

• Water depth, not tank wall height, is used — freeboard is excluded.

Limitations

• Conical or dual-drain bottom volumes are approximated by the cylindrical body.

Must be confirmed

• Supplier tank drawing and actual working depth

Convert stocked count, average body weight and survival into standing biomass.

Formula

• surviving_animals = stocked_count × (survival_% ÷ 100)
• standing_biomass_kg = surviving_animals × average_body_weight_g ÷ 1000

Biological assumptions

• A single population-average body weight is representative; size grading is ignored.

Limitations

• Sampling error on average weight propagates directly and linearly into biomass.
• Standing biomass, harvest biomass and annual production are distinct quantities — do not substitute one for another.

Must be confirmed

• Sample protocol (30+ animals across the unit)
• Actual mortality records

Express biomass per unit water volume and compare it against a system-specific planning band.

Formula

• density_kg_per_m3 = standing_biomass_kg ÷ water_volume_m3
• Status is a comparison against the selected system band: RAS 60–120, flow-through 25–60, cage 15–40, pond 2–10 kg/m³.

Biological assumptions

• Bands are generic system ranges, not species-specific limits. Species-specific ranges are held in the species assumption library.

Limitations

• No density shown here is universally safe. The achievable density depends on oxygenation, water quality, health status, husbandry and — in several jurisdictions — the legal licence limit.
• The band is not adjusted for temperature, species sensitivity or life stage.

Must be confirmed

• Legal or licensed maximum density at the site
• Oxygen and biofiltration capacity at peak biomass
• Veterinary and welfare review

Estimate a planning range for dissolved-oxygen consumption by the standing stock.

Formula

• hourly_O2_kg = biomass_kg × species_rate_mg_per_kg_per_h × temperature_factor ÷ 1,000,000
• daily_O2_kg = hourly_O2_kg × 24
• design_value_kg_per_h = hourly_O2_kg × 1.5 (50% planning margin)

Biological assumptions

• Consumption rates are species-level planning averages for grow-out, not measured site data.
• Peak demand occurs 2–4 hours after feeding; the 1.5× margin is a planning allowance for that peak, not a measured peak.

Engineering assumptions

• This is oxygen CONSUMED by the stock. It is not an equipment rating: transfer efficiency, background oxygen and altitude/salinity saturation must be applied before sizing any device.

Limitations

• Does not model biofilter, sediment or bacterial oxygen demand, which can be a large share of total system demand in RAS and biofloc.
• Emergency oxygen (power failure) is a separate calculation and is not covered here.

Must be confirmed

• Transfer efficiency of the proposed oxygenation equipment
• Emergency oxygen duration and backup design
• Engineering review of total system oxygen demand

Translate a pond oxygen demand into an indicative installed aeration power range.

Formula

• oxygen demand is converted to an aeration duty using the selected standard aeration efficiency (kg O₂ per kWh) and a site derating factor.
• installed_kW = required_kg_O2_per_h ÷ (SAE_kg_O2_per_kWh × derating)

Engineering assumptions

• Standard aeration efficiency is quoted by manufacturers under clean-water test conditions; field performance is lower.
• Derating for salinity, temperature and pond geometry is a planning allowance only.

Limitations

• Does not model oxygen stratification, night-time minima or circulation pattern, all of which change real aerator placement and count.

Must be confirmed

• Manufacturer field-test data for the specific aerator
• Aerator layout and circulation design
• Backup-power sizing for aeration

Compute realised FCR from feed used and weight gained, and compare it against a species planning benchmark.

Formula

• weight_gain_kg = ending_biomass_kg − starting_biomass_kg
• FCR = feed_used_kg ÷ weight_gain_kg (undefined when gain ≤ 0)

Biological assumptions

• Benchmarks assume a commercial extruded feed and managed water quality.

Limitations

• This is economic FCR when mortality feed is included in the feed figure, and biological FCR when it is not. The tool cannot tell which the buyer entered.
• No feeder, sensor or software product is claimed to reduce FCR.

Must be confirmed

• Whether mortality feed is included in the feed total
• Feed specification and pellet quality

Convert planned biomass gain and FCR into annual feed demand, storage requirement and feed cost.

Formula

• feed_required_kg = biomass_gain_kg × FCR
• annual_feed_cost = feed_required_kg × feed_price_per_kg
• storage_requirement_kg = daily_peak_feed_kg × storage_days (plus wastage allowance where entered)

Biological assumptions

• Feed demand tracks biomass GAIN, not standing biomass or harvest weight.

Limitations

• Feed price is a buyer input; FishMatch publishes no feed price benchmark as fact.
• Complete aquafeed manufacturing projects are out of scope and are routed to FeedMatch; on-farm feeding and storage equipment stays in scope.

Must be confirmed

• Supplier feed quotation and delivery frequency
• Local wastage and spoilage allowance

Derive required flow, indicative hydraulic and shaft power, and an indicative pipe diameter for pre-quotation discussion.

Formula

• flow_m3_per_h = system_volume_m3 × turnovers_per_hour
• hydraulic_kW = ρ × g × Q × H ÷ 1000, with ρ = 1000 kg/m³, g = 9.81 m/s², Q in m³/s, H = total dynamic head in m
• shaft_kW = hydraulic_kW ÷ (pump_efficiency_% ÷ 100)
• pipe_diameter_mm = √(4Q ÷ (π × 1.5 m/s)) × 1000

Engineering assumptions

• Total dynamic head is a user input, not a computed value — it must come from a hydraulic calculation of static lift, pipe friction, fittings and treatment pressure loss.
• Pipe diameter is sized at a 1.5 m/s design velocity, a common planning convention rather than an optimised result.

Limitations

• This is not pump selection. It does not produce a duty point, NPSH check, motor rating, duty/standby arrangement or a pump model.
• Add 15–25% design margin for filter fouling and future capacity before quoting.

Must be confirmed

• Full hydraulic calculation and system curve
• NPSH available at the pump
• Duty/standby and redundancy strategy
• Final pump and pipe selection by the integrator

Derive an indicative MBBR media volume and drum-filter flow from daily feed load.

Formula

• TAN_kg_per_day = daily_feed_kg × TAN_per_kg_feed_g ÷ 1000
• media_volume_m3 = (TAN_kg_per_day × 1000) ÷ media_nitrification_rate_g_per_m3_per_day
• drum_filter_flow_m3_per_h = system_volume_m3 × turnover_multiplier

Biological assumptions

• ≈30 g TAN per kg feed at ~45% dietary protein is a planning convention; actual excretion varies with diet and species.

Engineering assumptions

• Media nitrification rates (150–800 g TAN/m³/day) depend on temperature, dissolved oxygen, pH, alkalinity and biofilm maturity.
• Media volume is not reactor volume: K1/K3 media is typically filled at 40–60% of reactor volume.

Limitations

• Does not size CO₂ stripping, degassing, alkalinity dosing, denitrification, UV or ozone — all of which are required in a real RAS.
• No drum-filter model, micron rating, biofilter vendor or reactor geometry is selected.

Must be confirmed

• Integrator biofilter design at design temperature
• Alkalinity and pH control strategy
• CO₂ removal and degassing design
• Media supplier performance data

Derive the five planning-level RAS quantities — system volume, make-up water, feed load, TAN load and oxygen demand — from a target standing biomass.

Formula

• system_volume_m3 = target_standing_biomass_kg ÷ target_density_kg_per_m3
• daily_feed_kg = target_standing_biomass_kg × feed_rate_%BW ÷ 100
• make_up_water_m3_per_day = system_volume_m3 × make_up_% ÷ 100
• TAN_g_per_day = daily_feed_kg × TAN_per_kg_feed_g
• MBBR_media_m3 = TAN_g_per_day ÷ media_removal_rate_g_per_m3_per_day
• O2_kg_per_day = daily_feed_kg × O2_per_kg_feed_g ÷ 1000

Biological assumptions

• Feed rate as % of body weight per day is life-stage and temperature dependent; the default is a grow-out planning value.
• Target density must come from the species assumption library for the chosen species and system, not from a generic default.

Engineering assumptions

• Make-up water of 3–10% of system volume per day reflects modern RAS practice but depends on the treatment train and discharge consent.
• Oxygen per kg feed (~250 g) is a planning convention covering fish respiration; biofilter and bacterial demand are additional.

Limitations

• This is NOT a RAS design. It does not select a drum filter, biofilter reactor, pump, oxygen cone, ozone generator, UV dose or pipe diameter.
• It does not model CO₂, alkalinity, nitrate accumulation, heat balance, hydraulic layout, redundancy or biosecurity zoning.
• Culture volume is not total system volume — treatment loop, sumps and pipework add substantially.

Must be confirmed

• Full integrator process design and mass balance
• Heating/cooling load and energy balance
• Redundancy, alarm and backup-power design
• Discharge consent and effluent treatment
• Veterinary and biosecurity plan

Convert an exchange target into daily water volume and flow requirement.

Formula

• daily_exchange_m3 = system_volume_m3 × exchange_%_per_day ÷ 100
• continuous_flow_L_per_s = daily_exchange_m3 × 1000 ÷ 86,400

Engineering assumptions

• Assumes continuous, evenly distributed exchange rather than batch exchange.

Limitations

• Does not verify that the site water source can sustain the requirement, nor that discharge is permitted.

Must be confirmed

• Water-resource assessment and abstraction rights
• Discharge consent and effluent limits

Model vannamei pond yield, feed demand, revenue and feed-only gross margin per cycle and per year.

Formula

• stocked_animals = pond_area_ha × 10,000 × density_PL_per_m2
• harvested_animals = stocked_animals × survival_% ÷ 100
• harvest_kg_per_cycle = harvested_animals × harvest_weight_g ÷ 1000
• annual_harvest_kg = harvest_kg_per_cycle × cycles_per_year
• annual_feed_kg = annual_harvest_kg × FCR
• revenue = annual_harvest_kg × farmgate_price; feed_cost = annual_feed_kg × feed_price
• gross_margin = revenue − feed_cost (feed only — excludes all other OPEX and CAPEX)

Biological assumptions

• FCR is applied to harvest biomass rather than biomass gain, which slightly overstates feed for a heavily stocked PL cohort. Treat the feed figure as a conservative planning value.
• Survival is a scenario input. Disease events (AHPND/EMS, WSSV, EHP) can move it far outside any scenario shown.

Limitations

• Prices are buyer inputs. FishMatch publishes no shrimp price forecast as fact.
• No system, liner, probiotic, biofloc or automation configuration eliminates disease risk.
• Cycles per year are climate- and site-dependent and cannot be assumed.

Must be confirmed

• Post-larvae health status and hatchery source
• Site salinity, water source and discharge
• Aeration and backup-power plan
• Full OPEX build-up before any margin conclusion

Build an indicative CAPEX range from the buyer's own scope selections and unit inputs.

Formula

• equipment_capex = Σ(selected scope line items × entered unit rates)
• installed_capex = equipment_capex + installation + freight + duties
• total_project_capex = installed_capex + civil works + buildings + commissioning + training + contingency + initial working capital (where entered)

Limitations

• No single $/tonne CAPEX benchmark is universally applicable. Any headline figure shown is the direct arithmetic result of the inputs on screen, not a market benchmark.
• Land is included only when the buyer enters it.
• Freight, duties and local civil-works costs vary by country and by year and must be quoted.

Must be confirmed

• Supplier quotations for every equipment line
• Local civil works and construction pricing
• Freight, duty and import tax
• Commissioning and training scope

Produce revenue, margin, payback and break-even scenarios from the buyer's own CAPEX, OPEX, production and price inputs.

Formula

• revenue = annual_production_kg × farmgate_price
• operating_margin = revenue − annual_OPEX
• simple_payback_years = total_CAPEX ÷ operating_margin (undefined when margin ≤ 0)
• break_even_price = annual_OPEX ÷ annual_production_kg
• break_even_production = annual_OPEX ÷ farmgate_price

Limitations

• Simple payback ignores ramp-up, financing cost, tax, working-capital timing and residual value.
• A calculator output does not make a project profitable, viable or bankable. Those are conclusions for a feasibility study and a lender.
• Conservative, base and upside cases bracket input uncertainty; they are not probability estimates.

Must be confirmed

• Feasibility study and independent financial model
• Offtake pricing evidence
• Ramp-up curve for years 1–3
• Lender due diligence

Convert equipment loads and operating hours into annual electricity consumption and cost.

Formula

• annual_kWh = Σ(load_kW × operating_hours_per_day × 365 × utilisation_factor)
• annual_cost = annual_kWh × electricity_price_per_kWh
• energy_per_tonne = annual_kWh ÷ annual_production_tonnes

Engineering assumptions

• Connected load and average operating load are different quantities; this tool uses operating load × hours and does not report peak demand charges.

Limitations

• Does not model tariff structures, demand charges, power factor or seasonal variation.
• No energy saving is claimed for any product without a verified site baseline.

Must be confirmed

• Actual tariff and demand-charge structure
• Grid reliability and backup-power requirement

Show the arithmetic of a loan structure the buyer enters, for preparation purposes only.

Formula

• monthly_payment = P × r ÷ (1 − (1 + r)^(−n)), where r = annual_rate ÷ 12 and n = term_months
• total_interest = (monthly_payment × n) − P

Limitations

• Rates and terms are buyer inputs used for arithmetic only. FishMatch is not a lender, credit broker of record or financial adviser and publishes no expected rate, ticket size or approval outcome.
• Eligibility, pricing and terms are set solely by independent financing providers.

Must be confirmed

• Actual indicative terms from an independent financing provider
• Fees, security requirements and covenants

Nile tilapia (Oreochromis niloticus)

Salinity:

0–15 ppt — Freshwater culture is standard; brackish tolerance is strain-dependent and must be confirmed for the specific strain.

Dissolved oxygen target:

4–6 mg/L — Operating target above the stress threshold; peak demand occurs after feeding.

Grow-out period:

5–8 months — From ~20–30 g fingerling to market size, temperature-dependent.

Harvest weight:

500–900 g — Whole-fish and fillet markets differ; confirm the target with the buyer's offtake.

Stocking density by system

• pond: 2–10 kg/m³ — Semi-intensive to intensive aerated pond; depends on aeration and water exchange.
• ras: 40–80 kg/m³ — Requires validated oxygenation, biofiltration and CO₂ stripping capacity.
• cage: 15–40 kg/m³ — Site current and depth dependent; requires site assessment.

Limitations

• Strain genetics (e.g. improved vs unimproved lines) change growth and survival materially.
• Densities above the listed range are used commercially but require engineering and health validation.

You must supply

site water temperature profile · strain and fingerling source · feed specification

Whiteleg shrimp (vannamei) (Penaeus vannamei)

Salinity:

5–35 ppt — Broad tolerance; low-salinity culture requires ionic balancing and is not equivalent to coastal culture.

Dissolved oxygen target:

5–6 mg/L — Intensive ponds need continuous aeration; night-time minima drive the design.

Grow-out period:

90–130 days — From PL10–PL15 to market size, temperature and density dependent.

Harvest weight:

15–30 g — Count-size driven by the target market; larger sizes extend the cycle disproportionately.

Stocking density by system

• pond: 40–150 PL/m² — Intensive lined and aerated pond. Extensive systems operate far below this.
• biofloc: 150–400 PL/m² — Requires validated aeration, carbon dosing and solids control.

Limitations

• Disease pressure is the dominant variable and is site- and region-specific. No system design eliminates disease risk.
• Post-larvae quality and SPF status change survival more than any equipment choice.

You must supply

post-larvae source and health status · site salinity and water source · aeration and backup-power plan

Atlantic salmon (Salmo salar)

Salinity:

0–35 ppt — Freshwater to smoltification, then seawater. Transfer timing is a biological decision.

Dissolved oxygen target:

7–9 mg/L — Higher absolute DO than warm-water species because of the low temperature and high sensitivity.

Grow-out period:

14–24 months — Full cycle from smolt to harvest, site and temperature dependent.

Harvest weight:

4–6 kg — Whole gutted equivalents vary by market.

Stocking density by system

• cage: 10–25 kg/m³ — Regulated maximum in several jurisdictions — confirm the local legal limit.
• ras: 40–75 kg/m³ — Post-smolt production; requires validated CO₂ and TAN removal.

Limitations

• Maximum density is a legal limit in several producing countries, not only an engineering choice.
• Land-based full grow-out to harvest size is not yet a broadly proven commercial norm — treat plans conservatively.

You must supply

local density and licensing limits · smolt source · site temperature profile

Rainbow trout (Oncorhynchus mykiss)

Salinity:

0–30 ppt — Freshwater is standard; seawater culture requires acclimated stock.

Dissolved oxygen target:

7–9 mg/L — Flow-through outlet DO is the limiting design parameter.

Grow-out period:

10–16 months — To portion size, temperature dependent.

Harvest weight:

300–1200 g — Portion trout and large trout are different production plans.

Stocking density by system

• flow-through: 25–60 kg/m³ — Limited by inflow rate and outlet oxygen, not by tank volume alone.
• ras: 40–80 kg/m³ — Requires validated oxygenation and biofiltration.

Limitations

• Flow-through capacity is governed by water rights and inflow, which must be confirmed on site.

You must supply

available inflow (L/s) · water rights / discharge consent · inlet temperature profile

European seabass (Dicentrarchus labrax)

Salinity:

20–38 ppt — Marine and higher-brackish culture.

Dissolved oxygen target:

5–7 mg/L — Operating target for grow-out.

Grow-out period:

16–24 months — From juvenile to ~400 g, strongly temperature dependent.

Harvest weight:

350–600 g — Standard Mediterranean market sizes.

Stocking density by system

• cage: 10–25 kg/m³ — Site current, depth and licensing dependent.
• ras: 30–60 kg/m³ — Requires validated marine biofiltration.

Limitations

• Winter growth stalls materially in the northern Mediterranean; annual cycles are not uniform.

You must supply

site temperature profile · juvenile source · licensed biomass cap

Gilthead seabream (Sparus aurata)

Salinity:

20–40 ppt — Marine culture.

Dissolved oxygen target:

5–7 mg/L — Operating target for grow-out.

Grow-out period:

14–22 months — From juvenile to ~400 g.

Harvest weight:

350–600 g — Standard Mediterranean market sizes.

Stocking density by system

• cage: 10–25 kg/m³ — Site and licence dependent.

Limitations

• Winter feeding stoppages change annual production materially versus a flat-rate model.

You must supply

site temperature profile · licensed biomass cap

African catfish (Clarias gariepinus)

Salinity:

0–5 ppt — Freshwater culture.

Dissolved oxygen target:

3–5 mg/L — Air-breathing species tolerates lower DO than most finfish, but water quality still limits growth.

Grow-out period:

4–7 months — To ~1 kg market size.

Harvest weight:

800–1500 g — West African markets typically favour larger sizes; confirm locally.

Stocking density by system

• ras: 100–250 kg/m³ — Unusually high tolerance, but requires validated solids and ammonia removal.
• pond: 5–20 kg/m³ — Aerated intensive pond.

Limitations

• High-density tolerance does not remove the need for ammonia and solids control.

You must supply

target market size · fingerling source

Barramundi (Asian seabass) (Lates calcarifer)

Salinity:

0–35 ppt — Euryhaline; both freshwater and marine culture are practised.

Dissolved oxygen target:

5–6 mg/L — Operating target for grow-out.

Grow-out period:

9–15 months — To ~1–3 kg depending on market.

Harvest weight:

800–3000 g — Plate size and fillet size are different production plans.

Stocking density by system

• ras: 30–70 kg/m³ — Requires validated oxygenation and biofiltration.
• cage: 10–30 kg/m³ — Site dependent.

Limitations

• Size grading is a production requirement, not an optional step — plan tank/cage count accordingly.

You must supply

target market size · heating strategy for non-tropical sites