All types of nets for aquaculture

Solid nets that you can rely on

Knox have been making nets for fish farmers worldwide since the industry’s beginnings, producing a range of customised cage nets, bird nets, predator solutions, sweep and sampling nets. In conjunction with our partners, Garware Technical Fibres, we now also supply lice shields, treatment tarpaulins, wrasse hides and passive graders.

We are the Scottish and Irish distributor for Framo LiftUp mortality extraction systems and we hold stock in Ayrshire of all major components, ensuring a timely supply.

Recent development has seen us involved in net interface systems and mooring plates through our parent company, Selstad. 

Cage nets

When choosing the ideal rigging and netting specification for your cage pen, user preferences are taken into account along with cage type and site conditions. Our in-house FEA engineer can analyse your unique environmental conditions and we have practical input from the former fish farmers on our team.

We offer nets made from traditional stabilised knotless nylon netting, Dyneema or the tried and tested range of HDPE netting from Garware, including Sapphire SealPro and CFR, highly recommended when stiffer netting is required. These are now also available in coatable versions for the application of antifoulant.

Nets are completely custom-built, from the smallest freshwater pens to 200m circles.

Chat to us and build up the correct specification to suit your needs.

Bird nets

Bird nets to protect the surface of the cage are produced from polythene, nylon or a specialist mix netting, in mesh ranging from 50mm to 300mm square. Chafer panels to protect the net from the support are often added in the centre, using a heavy duty 25mm mesh netting. Recent advances have seen high poles used to raise top nets from the surface, with side panels incorporated into the design.

Predator control

Nets for effective predator control below the surface can consist of panels to surround one or a complete group of cages or can be complete with bases, produced from nylon or p.e. netting.

Rather than surround the cage net, why not rope an anti-predator base to the net? Sapphire Ultracore, developed by GWRL, is a knotted high density p.e. netting with a core enhanced by marine grade fine stainless steel wires and can be incorporated as an anti-predator base on cage nets, frequently covering both the base of the net and up to 6m of walls.

Other nets

We produce a wide range of other nets for practical use on fish farms: sweep nets incorporating floats at the top and leadline on the base; mortality baskets with a s/s frame made by our own engineers and either 15 or 25mm mesh; small box nets for sampling purposes and brailer nets, all designed and produced to suit your requirements.

Call us to discuss any ideas and we will translate them into practical products.

Fish health

Non-chemical products for better fish health are being continually developed and improved, in conjunction with GTFL. The robust and porous woven X12 material forms a barrier between the cage collar and net to exclude lice larvae. It can be tubular or overlapping, with monitoring showing better oxygen exchange than with standard polyester. Wrasse hides or even combination hides for all cleaner fish can be strung across the cage and are available in lengths to suit.

When chemical treatments are considered, we supply wedge and cone-shaped tarpaulins, and will repair and renovate as required.


If the addition of antifoulant coating to a cage net is part of your farm’s fouling management strategy, then you can rely on Knox to treat your net purchase before it leaves our factory. We have exclusive UK use of well-proven treatments from Steen-Hansen, including the copper-based AquaNet and biocide-free NetCoating or polish, which protects the net fibres during the washing process. All nets are fully dried before being despatched.


As Scottish and Irish distributor of the popular Norwegian Framo LiftUp mortality extraction systems, we hold stock in Ayrshire of all major components, ensuring a timely supply.

Call Alec Russell for quotes and advice on 07775 688037.

Glider System

The glider system is an operational net weighting and lifting system initially developed in Norway by our parent company, Selstad. Knox adapted it in 2022 for the high energy conditions and predation pressures experienced within the Scottish market, resulting in numerous high energy farms converting from tensioned sinker tube systems.

Major benefits include

The speed to lift and lower nets

The simplicity on the pen

Soft net weighting system

Improved net shape when lifting nets

Improved load distribution into the net from the weighting system

Capital investment and maintenance costs are also low. Call us for more details.


Together with our parent company, we have a multi-disciplined engineering team including mooring analysts accredited to tailor mooring systems to meet your needs. In order to offer steel-free moorings and to increase inspection intervals, Selstad has developed a plastic-coated mooring plate with a steel core, complete with holes to attached grid ropes, bridles, mooring lines and grid buoys. The plate’s weight of 540kg leads to increased inertia in the mooring system, leading to greater stability.

Contact us for more details.


Knox has been working with Fjord Solutions to bring the Aqualock to the Scottish market. This is a unique locking mechanism that allows sinker tubes to hang submerged during all farming operations. The Aqualock is connected between the sinker tube and the main net with a locking rope that goes all the way up to the pen deck. Using it avoids the use of divers and cranes and similar work on the net can be carried out from the surface. Speak to us and have a look at it yourself.