Catching and transporting a Koi is not difficult, it simply takes a little planning and practice. Even if you never plan to take your Koi anywhere you should be ready to. 
Have a plan, the necessary equipment and practice catching and moving your Koi. The more you practice, the more experience you gain, and the less stressed you and your Koi will get.
Limit food intake before the trip to minimize ammonia build up once bagged.
The ideal way is to guide the Koi into a tub and not to lift the Koi out of the water if possible. Then scoup the fish out into a bag.
Alternatively, turn the net sideways so it cuts through the water and lift it at the right time.
Try to keep the net in front of the Koi's face. There are no scales on the head that can be damaged by a net. 
Place the Koi in a plastic bag with just enough water to cover the fish then fill the bag with oxygene. (just cover the dorsal fin.)
Add 5-10 times the amount of oxygen as water
Only one large fish per large bag. Two refuse bags is quite suitable, especially the see through bags currently available.
Check your bags for leaks. It is not fun to get all ready to go and find water running out of a bag. 
For safety, use double bags and put rubber bands on both.
The oxygene will keep the fish alive for at least 3 hours.
Fish are remarkably well adapted for extracting oxygen from the very low concentrations found in water.
Water with an oxygen concentration of less than 3 mg/l will generally not support fish.
If oxygene is not available, use a bigger bag with more water, and if possible, pump air into the bag with a normal airstone pump. This will be suffiecient for at least a 90 minute trip.
If a transport tank is being used for moving fish, an air stone or a tyre compressor can be used, connected to your ligher power supply. 
Leave enough surface area in the bag to allow for gas/air exchange.
Cover the bagged fish to eliminate light and keep bagged fish out of direct sunlight and as cool as possible. Use an ice pack for longer trips. The cooler the water, the longer the oxygene will stay in the water. Koi are cold blooded, that is, their body temperature is essentially that of their environment.
Place the bag in a box for the trip to prevent injury to the fish, especially big fish.
The metabolism and activity increase with temperature which increases their oxygen demand.
It is important to remember that as fish respirate they create carbonic acid. The alkalinity of the water will try to neutralize the acids produced by the feaces of the fish. As a result you will find the pH drop. As a result, the ammonia the fish are producing will be converted to ammonium which is a far less toxic substance. 
Place the head of a large fish directing towards the back of the vehicle. You do not want to convert the fish into a bull dog after a sudden brake.
Before you release the fish at your destination, never add water to the bag. The ph will shoot up and convert the ammonium to toxic ammonia.
When reaching the destination, release the fish as soon as possible but float it for at least 10 minutes. Why float the bag for another 25 minutes with low oxygene and high ammonia levels in the bag, unless there is is a big difference in water temperature?
Do not release the water in the bag into the pond. It might contain parasites and will contain ammonia.
Gently remove the fish from the bag and place it in the pond/quarantine facility, either with your hands or with a soft net. At this stage it is a good time to check for any injuries and you might want to measure your fish at this time before your release it.
Do not release the old water into the new pond.
Increase the salt contents of the water.
Cover the pond(new environment) with a net because they may jump. 

I am flying to Durban and someone is selling his collection. I might bring two big ones back. I've red this post. Just a few questions:

1. I see that one fills up to the dorsal fin and then oxygen, but they state a 3 hour period. I am just worried that the whole trip might be say 4 hours or even longer.
2. If one put them in the box, can you just book it in as fragile, or do I need to make special arrangements. I am flying SAA

Any other comments/tips?? You guys that show, must know all the tricks!

Hi albie

Others will be able to give you more info about the shipping procedures but i can guarentee you that the koi will be able to last much longer than 3 hours in the bags.

if you think about it koi spent about 14-16 hours in the bags when being imported from Japan. To get to cape town they fly Tokyo to Jo Burg get offloaded and uploaded onto another flight to reach Cape Town. Once arrived here it takes another 2 hours to get pass customs. To minimize the risk with big fish, bag each fish seperately.

I assume that you will be transporting your koi as livestock on the plane and not as general goods.

Hi Albie

If you put pure oxygen into the water, the fish will be fine for at least 18 hours. Without pure oxygen, up to three hours, but I will not fly any fish without pure oxygen. Temperature makes a huge difference and obviously the amount of fish in a bag.

When I Import fish from Japan, my fish goes from Niigata to Tokyo to Amsterdam to Johannesburg to Cape Town. Fortunately we pre-clear the fish, so that custom clearance don't take too long on arrival. Department of Agriculture inspects the fish on arrival and your are clear. I arrange my flights so that it arrives at night. It makes it much cooler, and the clearance with customs takes much quicker.

This trip sometimes takes approximately 50 hours, but a product called Allfish are being added to the bags. It comes in two small bags which are being inserted into the plastic bag with the fish. It provides additional oxygen during the trip and removes Ammonia. My agent also adds gel packs to keep the temperature down.

If you wish to fly your fish, you have to book them with the gargo section prior to the day of flight and they will provide you with a waybill number. They must fly as live goods. With SAA you have to deliver the fish to the cargo section two hours before the flight. SA Airlink will be one hour. Allow at least 50 minutes before they will be released at the destination.

Remember not to feed the fish at least three days prior to the flight to prevent Ammonia in the bags.

They offload fish and other live stock first.

Hope this helps.

Thanks for the info Paul

I'm flying to Durban this afternoon and will speak to them at the airport. I return Wednesday evening.

Albie

Hi,

Quote :

Place the head of a large fish directing towards the back of the vehicle. You do not want to convert the fish into a bull dog after a sudden brake.

I would rather place the bag parallel with the axle on the vehicle.
Also check if there is any “needle” at the anal-fin, generally with bigger Koi, when using a bag.

Hi, I have a pond which holds 28000l of water. My Koi are between 12cm and 25cm long. How many can I keep in there max.?
For transporting my vet recommended an anti-stress herbal drop that one puts in the water prior to transport. On the bottle it reads: Natural Stress Treatments. Reduces erratic behaviour. Prevents fungal and other stress related infections. Relieves skin irritation. Increases cellular repare. Regulates mucous production. the manufacturer is Boi-elite and the product is anti stress. Does anyone know if this effective and safe at all?