Koi Pond Netting: What You Need to Know

As in many decisions regarding koi keeping, there are numerous choices regarding how to protect your koi and maintain water quality by keeping unwanted nature out. Covering your pond with a net is one of those choices.

What works for some, doesn’t work for others. Some enthusiasts even come up with their own interesting takes on how best to cover their ponds. All nets have their own merits and drawbacks. Cost, type of use, longevity, functionality, accessibility and aesthetics all factor into what type of pond netting is best suited to covering a pond.

Net Composition

The composition of the net is an important consideration. You will read stories from enthusiasts about how netting can be harmful to a koi that jumps or rubs against it, ripping fins and removing scales—which can cause infections.

Many nets on the market are made of the thermoplastic polymer polypropylene or polyethylene. It is UV stabilized to help protect against the effects of the sun. They are more prominent in extruded, knitted and shade cloth types of netting.

An alternative is nylon. Also a synthetic polymer, it is a product that is extremely durable. Probably more so than its polypropylene counterpart. It is also more resistant to rotting. Nylon is ordinarily in the knotted or woven form.

Knotted

Ordinarily made from nylon, it is aptly named with the intersection of each square (or diamond) having a knot at each square or diamond junction. It also floats and has a high tensile strength and as such are often used as a form of child-proofing a pond, too. The knots however, can be the culprit for some nicks and scrapes on your airborne koi.

Weaved

Essentially a knotted net minus the knots. The nylon net is a strong and durable material that doesn’t share the knotted’s tensile strength, but can be cut without issue and is a little “softer” than the knotted variety.

Knitted

Knitted netting is a plastic polypropylene monofilament style net and is less likely to injure any jumpy koi as it is softer than the knotted or weaved fabrics. The sawtooth pattern also allows for extremely small spaces in the mesh.

Extruded

One of the more common types of plastic pond netting. It is a lightweight yet strong material that comes in continuous, unbroken strands. It can be cut to size without the fibers fraying or unravelling. However, it can be tough on koi scales.

Shade Cloth

Shade cloth is another option. Primarily made out of polypropylene the mesh is extremely close, as small as ⅛”, meaning that it helps to block a large portion of the sun out (up to 70%), thereby keeping the pond cooler as well as debris free.

Shade cloth can also be put over a frame to keep it off the surface of the water and better.

Mesh Designs

Netting comes primarily in 3 different patterns: square, diamond and sawtooth. Whereas diamond and square are common to both types of material, sawtooth is unique to the plastic polypropylene fabric.

Some styles of nets (usually knitted and shade cloth) also come with grommets that allow for staking into the ground to keep the netting taut. The metal-reinforced options (primarily brass) will last longer under the rigors of being in the elements and the changing seasons.

Mesh Gap Sizing

Depending on the material used and the configuration of the patterning, the spaces between the fabric can come in a variety of different sizes. The increments are:

• ⅛”
• ½”
• ⅜”
• 11/16”
• ⅝”
• ¾”
• 1”
• 1 ¾”
• 2”

The bigger the holes, the less visible the netting is, but it does allow for increased access to the fish underneath by predators and leaves.  Other falling detritus can also get into the pond underneath.

While the tighter weaves are more visible, they have the benefit of keeping more of nature out of the pond while keeping your koi in it.

Pond netting can come from a variety of different sources from netting that was intended for a different purpose. Enthusiasts have turned to netting that was used for other purposes but found its way over their pond.

Some of the choices include:

Bird netting

Golfball/Soccer net

Shrimp nets

Swimming pool leaf nets

Some Things to Remember

Netting is not only a way to keep unwanted visitors out of your pond, it is also a good way to keep out the type of debris that can affect your overall water quality—and so, the health of your koi.

The materials used for the most part fall under the same types used for “pond” netting. Again, it is important to choose the correct size mesh spacing to match the size of the koi that are underneath and what you are trying to keep from getting in.

A 1” netting gap might be sufficient to keep Blue Herons out but not acorns or smaller leaves that will block filters, discolor water, end up in your koi’s diet and even throw your water quality out of sync.

A fiberglass or plastic pole across the center of your pond can also help against any sagging which will keep the leaves off the surface of your pond.

If you remove your netting after spring, washing it in soapy water can help to extend the life expectancy of your netting.

Any pond netting also needs to be very well secured. If it is not staked securely or fastened down with heavy enough objects, the creatures that are capable of going under the net (otters, raccoons, cats, minks) will enjoy an awning while they pick up a meal.

A clean pond and a safe koi can be a huge weight off any pond keeper’s shoulders. Look and ask around as to which type of netting will best suit your pond and your needs. It is literally not a one size fits all proposition. Oak leaves are bigger than pine needles and herons won’t go as low as a raccoon. Knowing your surroundings and your potential threats is extremely helpful.