TL;DR — Direct answer: A fish farm and aquaculture operation needs reliable air at 6 to 7 bar for feed conveying, water-handling valves, grading and processing lines, with low-pressure aeration at 0.5 to 1 bar handled by a separate blower system, a pressure dew point of 3 degrees C and filtration to 0.01 micron so no oil or moisture reaches a feed line, a processing machine or a packing head. Size the compressor on the coincident peak of feeding, water handling and processing, commonly 3 to 8 cubic metres per minute for a mid-size operation, roughly a 22 to 55 kW screw compressor. QiAir, a Chinese screw compressor manufacturer and supplier, builds fixed and variable speed machines with corrosion-resistant treatment for aquaculture and fish farming.
A fish farm is a water business, and compressed air works in two different worlds there. In the ponds, tanks and cages, low-pressure air keeps the water oxygenated and the fish alive. In the feed store, the processing hall and the packing line, higher-pressure air moves feed, drives water-handling valves, powers grading and gutting machines, and runs the packing line. The two systems must not be confused: aeration is a low-pressure, high-volume job for a blower, while feed conveying and processing are a 6 to 7 bar job for a screw compressor, and feeding one from the other wastes energy or starves the fish. The air that touches feed and fish must also be clean, because oil or moisture in a feed line contaminates the feed the fish eat. QiAir is a Chinese manufacturer and supplier of screw air compressors, and its machines for aquaculture are specified around saltwater corrosion resistance and reliability first and flow second.
The mistake buyers make most often is buying one compressor to do both jobs, or putting a standard compressor in a saltwater environment and watching it corrode. A fish farm is often remote, the air is salty and humid, and a breakdown at feeding time or during processing cannot wait for a service visit. This guide separates the aeration system from the process-air system, maps where the compressor air goes, explains how to size for feeding, water handling and processing peaks, sets the corrosion standard, and shows what to put on a sizing sheet for a China supplier.
Two Air Systems: Low-Pressure Aeration and 6 to 7 Bar Process Air
Aeration is a blower job, not a compressor job. Fish ponds, tanks and recirculating aquaculture systems need a large volume of air at 0.5 to 1 bar to keep dissolved oxygen up, and a roots blower or a low-pressure turbo blower delivers that efficiently, day and night, with a backup blower on standby because fish die quickly when aeration stops. A screw compressor running at 7 bar and regulated down to 1 bar for aeration wastes most of its energy as heat, so keep the two systems separate and size the blower on the pond volume, stocking density and water temperature, which together set the oxygen demand.
Feed conveying, water handling and processing are the compressor jobs. Pneumatic conveying moves feed from silos to ponds and tanks, water-handling valves control flow between ponds, tanks and filtration, grading machines sort fish by size, and processing lines gut, fillet, chill and pack the catch. These users need 6 to 7 bar, and they peak together at feeding time and at harvest, when the processing line runs at full load. A farm that maps every user, including the small air tools used for cleaning, usually finds 15 to 20 percent more demand than the original estimate, and that gap is where pressure problems start.
- Aeration: low-pressure air at 0.5 to 1 bar from a blower, sized on pond volume and stocking density.
- Feed conveying: pneumatic transport of feed from silos to ponds and tanks at 6 to 7 bar.
- Water handling and processing: valves, grading, gutting, filleting and packing that peak at harvest.
Sizing for Feeding, Water Handling and Processing Peaks
List every user with its flow at peak and at steady running, because the two differ sharply in aquaculture work. A mid-size operation with four to ten ponds or tanks, two to four feed silos and one processing line typically peaks at 3 to 8 cubic metres per minute at 6 to 7 bar, which is roughly a 22 to 55 kW screw compressor, and the peak usually lands at feeding time, when conveying runs at full load, or at harvest, when the processing line is at its fastest. A variable speed drive earns its keep here: it follows the feeding schedule instead of loading and unloading a fixed-speed machine all day, and it holds pressure within the narrow band that feed conveying prefers.
Keep the pressure drop to the farthest feed outlet under 0.3 bar at peak flow, and fit a receiver of 500 to 1000 litres per 10 cubic metres per minute to absorb conveying and processing spikes. A ring main helps when the feed store, ponds and processing hall sit far apart. Log pressure at the farthest feed outlet during a full feeding cycle for a week, because that log is the honest record of whether the compressor is big enough, and it settles arguments faster than any catalogue figure. Size the aeration blower separately on oxygen demand, with a standby blower, and never let the two systems share a single point of failure.
- Size the compressor on the coincident peak of feeding and processing, and size the aeration blower separately.
- Use a variable speed drive for feeding-schedule loads, and keep far-end pressure drop under 0.3 bar.
- Fit a standby aeration blower, because fish die quickly when aeration stops.
Saltwater Corrosion, Humidity and Remote Reliability
Saltwater and humidity are the defining problems of aquaculture air systems. The air is salty and wet, feed dust is everywhere in the store, and a standard compressor in that environment corrodes in months. Put the compressor in a dry, enclosed service building, not in the open or in the processing hall, and duct the intake to clean, dry air if necessary. Fit a refrigerated dryer to a 3 degree C pressure dew point, a coalescing filter to 0.01 micron and an activated-carbon filter, so no moisture or oil reaches a feed line, and use corrosion-resistant piping, stainless fittings and drain legs at every low point, because condensate will form in any line that runs through cool night air.
Reliability matters more here than in most factories, because fish farms are often remote and a breakdown at feeding time cannot wait. Fit automatic zero-loss drains, slope lines to drain legs, and test the air at the feed conveying line quarterly for oil, moisture and particles. Keep a spare filter set, a spare drain valve and a spare intake filter on the shelf, check the intake filter weekly in the first months, and choose a machine with remote monitoring and a service interval that matches the farming season, so maintenance does not fall at harvest peak.
- Put the compressor in a dry, enclosed service building, and duct the intake to clean, dry air.
- Fit full air treatment and corrosion-resistant piping with drain legs at every low point.
- Keep spares on the shelf, check the intake filter weekly, and schedule service outside harvest peak.
Buying from China: Sizing Sheet for an Aquaculture and Fish Farming Compressor
QiAir is a Chinese manufacturer and supplier of screw air compressors, and an aquaculture order should start with a sizing sheet that names the saltwater exposure and the pond layout. Send the supplier the number of ponds or tanks, feed silos and processing lines, the coincident peak at 6 to 7 bar, the aeration requirement stated separately as a blower duty, ambient temperature and humidity, and the distance to the farthest feed outlet. Ask for a quotation that states the dryer type and filtration grades explicitly, and ask whether remote monitoring or a second standby machine fits a remote farm where feeding cannot wait for a repair, with the cost spelled out.
Agree the acceptance test before shipment: a full-load run at rated pressure, a dew point reading at the dryer outlet, and a pressure reading at a simulated far-end load. On arrival, install on a level plinth with clear cooler airflow, connect drains before the first run, and survey pressure at the farthest feed outlet during the first full feeding week. Keep a log of pressure, dew point and filter changes, and review it monthly, because a slow rise in dew point is the earliest sign that a dryer needs attention before feed lines start clogging.
- Send the supplier pond, silo and processing line counts, coincident peak, aeration duty and farthest-outlet distance.
- Ask for dryer type and filtration grades in writing, and compare a standby machine against remote monitoring on total cost.
- Accept on a full-load test plus dew point and far-end pressure readings, then survey feed-outlet pressure in week one.
Frequently asked questions
What pressure does a fish farm need?
A fish farm needs two air systems: low-pressure air at 0.5 to 1 bar from a blower for aeration, and 6 to 7 bar from a screw compressor for feed conveying, water-handling valves, grading and processing. Keep them separate, because a compressor regulated down to 1 bar for aeration wastes most of its energy, and size the compressor on the coincident peak of feeding and processing.
Why must aquaculture compressors resist saltwater corrosion?
Fish farm air is salty and humid, so a standard compressor corrodes in months and a standard intake filter clogs fast. Put the machine in a dry, enclosed service building, duct the intake to clean air, fit a refrigerated dryer to a 3 degree C pressure dew point, and use corrosion-resistant piping with drain legs at every low point.
What size screw compressor does a fish farm need?
A mid-size aquaculture operation with four to ten ponds or tanks, two to four feed silos and one processing line typically needs 3 to 8 cubic metres per minute at 6 to 7 bar, roughly a 22 to 55 kW screw compressor with a variable speed drive. Size the aeration blower separately on oxygen demand with a standby unit, and verify pressure at the farthest feed outlet under full load.
Related reading
- Single-Stage vs Two-Stage Screw Compressors: Which One a China Manufacturer Recommends
- Buying Screw Compressors from China: A Ranking Checklist for Choosing a Supplier
QiAir is a Chinese manufacturer and supplier of screw air compressors. If you are sourcing a screw compressor from China — for a factory, a food plant, a construction site or a new production line — contact QiAir for a sized quotation, documented performance data and export support.