Which parameters are critical for fry and hatchery production in ras?
The critical parameters are temperature, dissolved oxygen, pH, ammonia, nitrite, nitrate, stocking density, feeding rate, hydraulics and redundancy of key equipment.
Technology - RAS for fry
Technology for growing fry in RAS systems
The RAS fry farm produces not “tons”, but high-quality planting material: high survival rate, uniformity in size and predictable growth. We analyze the environmental parameters, stages of cultivation, farm composition and equipment.
Incubation and larval section of a RAS fry farm
Short answer
Fry and hatchery production in RAS explains how to organize fish production with controlled water quality, oxygen, temperature, stocking density, feeding and routine operations. Fry systems need stage separation, gentle hydraulics, sanitation, precise feeding and stable water at each development stage.
What is a RAS farm for fry?
RAS fry farm is a farm focused on obtaining planting material of a given weight (larva → fry → juveniles) under controlled conditions with water reuse.
Key product for fry
Not the tonnage, but the quality of the batch: survival, uniformity in size, health, predictability of growth and readiness for transport and stocking.
Tasks of fry farms
Depends on the business and the type of fish - but usually comes down to several scenarios.
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Your own planting material
Providing your own commercial farm means savings and independence from the market.
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Supplies to farms
Sale of fry and juveniles to commercial fisheries.
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Paid reservoirs
Stocking of fish according to the reservoir format and season.
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Compensatory stocking
Restoration of aquatic biological resources according to the terms of the project.
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State programs
Reproduction of aquatic biological resources (less often for the private segment).
Types of fry farms
Classification “to the point” - to immediately understand what exactly to design.
By type of aquatic organism
Trout and salmon, sturgeon, catfish and others.
By product stage
Fertilized eggs → larva → fry (5–10 d) → juveniles (50–100 d).
By strategy
Own broodstock (full cycle) or purchase of fertilized eggs / larvae.
According to water technology
RAS (closed cycle), partial circulation or direct flow - depending on the water source.
Basic Environment Settings
For fry, the water requirements are stricter than for the fish: the early stages react more strongly to ammonia, suspended matter, temperature fluctuations and oxygen. Specific norms are set by species and stage.
| Parameter | Landmark | Comment |
|---|---|---|
| Temperature | by type and stage | Stability is critical, especially during incubation and larvae. |
| Oxygen (O₂) | high, no dips | In the early stages, any failure has a dramatic impact on survival. |
| pH | near neutral | It should be convenient for both the fish and the biofilter. |
| Ammonium/ammonia | minimize | Early stages are most sensitive; Calculation of the biofilter and water exchange is required. |
| suspension | minimize | Affects the gills and stress, reducing the quality of the fry. |
| CO₂ | control | With dense plantings and weak degassing, it affects growth and condition. |
| Iron/impurities | water analysis | In case of problematic water, water treatment units are required. |
Growing options
cages
Tied to the body of water, temperature and oxygen; it is more difficult to ensure consistent batch quality and biosafety.
Forward flow
Easier in engineering, but critically depends on the water source and seasonality; water requirements are high.
RAS
Maximum controllability in terms of environmental parameters and biosafety; stable batches all year round.
Design Features
- Thread logic: “dirty” operations (sorting, catching, packaging) should not contaminate the incubation and larvae.
- Separation of stages: incubation, larvae, starting feeding, rearing often require different containers and modes.
- Mechanical cleaning before biofilter: remove the suspension before biotreatment, and do not “twist” it in a circle.
- Oxygen and redundancy: on a fry, this is insurance number 1 - an accident means instant losses.
- Biosafety: quarantine of input material, disinfection barriers, UV/ozone as necessary, personnel flow management.
- Autofeeding and control: Frequent feedings in small doses and monitoring of eatability.
- Ergonomics: convenient sorting, washing, disinfection and quick access to RAS units.
Growing technology
From eggs to commercial fry there are four key stages.
Incubation of eggs. Your own broodstock or purchase of fertilized eggs (often at the “eye” stage). Incubation in specialized incubators with temperature, flow and O₂ control.
Aging and larva. The transition from hatching to feeding is a critical period: stable water and minimal stress. If necessary, a block of live food / brine shrimp.
Fry and growing up. Transition to starter extruded feed, control of palatability, regular sorting. Growing to the target weight.
Pre-sale preparation and shipment. Batch stabilization, health control, oxygen and temperature packaging, labeling and documents.
Stern
- High quality extruded starter feeds (often imported brands).
- Selection of faction for the stage; Transitions are made gradually.
- For certain species - live food (artemia for sturgeon, according to technology).
Planting material
- Your broodstock: more expensive and more complex, but provides autonomy and predictability.
- Purchasing eggs/larvae: easier and faster start, but dependence on the supplier and logistics.
Site and building
A typical checklist of site requirements.
- Water: source + water analysis, possibility of replenishment according to the meter.
- Electricity supply 380 B and redundancy of critical nodes.
- Heat: gas or alternative heat generation (especially for warm-water species).
- Sewerage and collection of wash water/sludge; Pre-cleaning and settling is desirable.
- Zoning: clean areas (incubation, larvae) and work areas (sorting, shipping).
Example of scale (guideline)
Area ~300 m² → up to 250 thousand trout fry ~5 g per cycle; for up to 6 generations/year - up to 1,5 million pcs/year (with suitable regimes and sales).
Farm composition
- Incubation block
- Larval block
- Live food / brine shrimp block (optional)
- Fry block (growing) + sorting
- Pre-sale preparation and shipment
- RAS core: mechanical cleaning → biofilter → (degassing) → oxygen → pump
- Instrumentation and automation + alarm
- Administrative technical premises: control room, laboratory, warehouses
Equipment
Typical composition of equipment for fry RAS. The list depends on the type of fish and water quality.
Pools and tanks
Drum filter
Biofilter
Oxygenator
Oxygen station
Degasser
Instrumentation and control panel
Pumps and hydraulics- Incubators and larval containers
- Swimming pools for fry and growing
- Monitoring and automation (sensors, alarm)
- pH adjustment (by water)
- Autofeeding (by task)
- Oxygenation / aeration with reserve
Resource costs
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Stern
Often the main expense is OPEX.
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Planting material
If you purchase caviar, larvae or fry.
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Electricity
Pumps, oxygen/aeration, automation.
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Warmth
Warm water regime or temperature stabilization.
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Staff
Qualified fish farmer + RAS operator.
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Water
Make-up according to the meter and purification of wash water.
CAPEX usually includes building and communications, process equipment, installation and commissioning.
Example modes: juvenile trout
Approximate water parameters by stages of trout growth (from incubation to main lines).
| Parameter | Incubation | Fry up to 0.3 g | Fry line | Main lines |
|---|---|---|---|---|
| Temperature, °C | 10–12 | 10–11 | 13–18 | 14–17 |
| pH | 6,8–7,5 | 7–8 | 7–8 | 7–8 |
| Oxygen, mg/l | 10–12 | 10–12 | 10–12 | 10–12 |
| NO₂, mg/l | 0–1 | 0–1 | 0–1 (up to 3) | 0–0.25 (up to 0.5) |
| NO₃, mg/l | up to 120 | up to 40 | up to 120 | up to 120 |
| Density | 8–10 thousand/frame | 10–15 thousand/tray | up to 15 kg/m³ | up to 50 kg/m³ |
Reception and adaptation of imported caviar
Trout caviar is often received “by hail days” (about 230–240 at the time of shipment), at a temperature in the package of 3–7 °C. Adaptation to plant water - at a speed of ~1 °C per hour, at pH 7–8 and O₂ 10–11 mg/l, then treatment against saprolegniosis.
Project implementation
Technology design — our profile (service “Design of fish farms”).
Building design.
Supply of equipment.
Construction of a building.
Installation of technology.
Launch and stocking.
We will design a fry farm to suit your needs
From the type of fish and target weight to the selection of equipment and working documentation.
Completed projects
Hatchery and fry farms that we have sold: trout (Leningrad, Ulyanovsk regions, Republic of Karelia) and sturgeon (Moscow region).
FAQ
Frequently asked questions
Clear answers to the questions that usually appear before a RAS fish farm project starts.
Can standard equipment be used without calculation?
It is risky. Equipment must match the species, biomass, feed load, water quality and building layout. A generic set can lead to weak filtration, unstable oxygen or difficult maintenance.
How is the technology selected for a project?
The choice depends on fish species, target capacity, water source, climate, available building, energy costs, staff skills, market format and the required level of automation.
Calculate a fry farm to suit your conditions
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