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How to Transport Koi with Polythene Bags

Koi transport is one of those unique packaging situations that the NPF Packaging team loves to get stuck into. Getting prize-winning koi from A to B is a challenge – and not just because you’ve got to catch them first! The problem is made especially difficult when transporting koi by air, because they won’t be travelling alone, and need strict environmental control to keep them healthy and happy.

But this is something of an area of expertise for us. We’ve worked closely with a koi carp company, supplying their inner and outer packaging for koi transport, as well as more complex solutions for moving fish to and from shows.

And it’s important to know the difference in transport packaging requirements. Koi keeper events are a global phenomenon, and trading these animals can involve movement around the world. That’s a far bigger and more challenging undertaking than taking a new koi home in your car, or delivering them by road through a specialist courier.

So, in this post, we’ll share what we’ve learned about how to transport koi fish, and what we recommend using as koi transport bags.


A single white and orange koi fish, poking its gaping mouth out of dark water


Transporting koi – what you need

The biggest thing to consider is the safety of the animal. Koi are not just extraordinarily expensive (the most expensive koi ever sold went for around $2 million), they’re living things that are highly sensitive to rapid changes in their environment.

Any kind of transport is going to be a stressful experience for them in some way, even if they’re one of the more relaxed-looking creatures on the face of it. Stress is a fish killer – so reducing it is key to getting koi to their destination in top condition.

But the bags you use need to be leak-proof, and a rigid outer packaging layer is required to prevent crushing, bursting and rolling. So let’s take a look at what you’ll need to package koi for transport:

Polythene bags and cable ties

Polythene koi transport bags must be large enough to hold the fish plus around 20cm of its length. The fish must be fully immersed in water when they’re in the bag, too. Don’t forget to buy extras – you’ll want to double bag the fish, and have spares in the event of a leak!

Medium duty polythene bags (200 to 400 gauge thickness, depending on fish size) are perfect to use for koi transport bags, giving the perfect strength to weight, and high clarity – which makes safety checks easier at a glance.

Learn more – Polythene thickness chart

Virgin material should be used to prevent any contamination, and bottom gusseted bags should be used that will perfectly fit into the outer box. Gusseted bags are far stronger and more leak-resistant than standard, single seal polythene bags, and allow for more precise fitting. They also reduce the number of corners that can poke and prod the fish in transit, and they can stand upright without rolling over.

Cable ties should be used to create a strong, watertight seal around a well folded top.

Rigid outer boxes or coolers

The outer packaging is equally important. Depending on the transport type, a very strong, rigid cardboard box can be used, or a reinforced polystyrene casing. If the fish are travelling a long distance, or by air, a cooler box (with ice packs at the bottom) is highly recommended. 

This maintains a steady, cool water temperature and helps further protect the fish from crushing, leaks, and bursts.

If you’re driving, remember to load the packaged koi into the vehicle at 90º to the direction of travel. If you don’t, they’ll bump their nose and tail every time you stop and go. This can cause discomfort and even injury, so drive carefully.

Salts and water conditioners

Water treatment will be required (like chlorine remover and aquarium salt), to prevent the onset of disease from sudden shock, and to prevent chlorine poisoning. If you’re using pond water, you can skip this – but you’ll still need an oxygen supply either way.

Pure oxygen and air pumps

Despite what many people believe, fish don’t breathe water – they breathe oxygen just like us! They extract oxygen from the water through their gills. In their pond or aquarium, the fish will get a constant supply of oxygen from the air around them, or from an air pump bubbling up the water.

In a sealed polythene bag, there is a very small amount of air which will quickly get used up, especially if the fish is stressed out. So pure oxygen is usually pumped into the bag just  before sealing, and for longer distances, a battery powered air pump might be installed.

Preparing and packaging your koi

The week before

In the lead up to the move, don’t feed your koi. They’ll get enough food naturally from foraging – but limiting their diet for a week or so just means they’ll contaminate their bag less in transit.

On the day

Before you attempt to catch them, make sure everything is ready and within arm’s reach, to limit out of water time: boxes, bags, cable ties, treated water and oxygen canisters, plus some towels. Pre-fill the bags with treated water, enough to reach the koi’s gills, and make sure you’ve got someone to help you, too!

Now, you’ve got to catch them… But chasing your koi around the pond with a net is going to stress you and the fish out – a lot. 

So, instead of chasing, lure them in with their favourite treat. Koi can’t swim backwards very well, so keep the net in front of them, and be careful of them trying to swim around it to get to the treat (cheeky fish).

Once you get the koi in the net, it might try to jump out, so move swiftly but safely.

With an extra pair of hands to help, move the fish into a pre-filled bag, and invert the net. Check the depth, and add more water if required. Don’t add too much though, because oxygen is the real priority, not the water.

Once you’re happy with the water level, remove as much air as possible and then pump in the pure oxygen. Inflate the bag to the limit of the outer box, but be careful not to pop it.

Seal the koi bag tightly with a cable tie, and then dry off the outside.

Now, inspect the fish and the bag for any damage, before double bagging and lovering the koi into the outer box (or cooler). Seal it up, and carefully load the fish into your car, van or courier vehicle.

Remember – face the fish 90º to the direction of travel!

Once you’ve done this, the clock will be ticking on the koi’s oxygen supply and water temperature, so it’s important to get going to your destination straight away.

On arrival

When the fish arrive, they’ll be tired and stressed – just like we are after a long trip. To keep them healthy, it’s recommended that koi are quarantined away from other fish to prevent them getting ill, as stress weakens the immune system. Water quality takes precedence here, and a little extra aquarium salt can help keep diseases at bay.

Koi can be safely quarantined without food for up to two weeks, but if the quarantine tank has good filtration, or you’re prepared to do a 25% water changer weekly,  then feed away.

If the koi have returned from a show, remember that diseases can be transmitted from other fish quite easily. You might want to double their quarantine time when they’re back, to get on top of any symptoms before infecting the rest of your fish!

Buy koi transport bags from NPF Packaging

Our team of polythene experts at NPF Packaging knows how to deliver simple solutions to complex problems – including koi transport. If you’re looking for koi transport bags from a seasoned team of professionals, click here to get a quote now, or call us on 01773 820415.