Float fish in the bags for 10-15 minutes (out of direct sun).  Do not put water from any other source in your water garden.

If at all possible, quarantine fish for a minimum of 14 days in their own quarantine tank. Take one of your fish and add to the quarantine tank.  This allows you to watch for potential problems with crossover bacteria and stress.  Its better to test one of your fish with the new ones in a smaller quarantine tank than to test the new ones with all of your fish in your pond.   

PH should be 6.5 - 8  
Ammonia 0 PPM 
Nitrite less than .25 PPM
Good oxygenation is required.

Ideal Salinity levels should be .3% (3 lbs of pond salt for 100 gals pond water).

 Do not mix our fish with fish from other sources during quarantine. Pick one supplier and stick with them.

Cover your tank, as new fish will jump.

Add Microbe Lift Fish Protector or Melafix or Stress Coat to quarantine tank or watergarden following product directions.

When adding new fish to your water garden or koi pond after quarantine, watch fish closely for problems.

If you choose not to quarantine, do all you can to insure the health of all your fish.

There are deadly fish diseases.  Make sure your fish come from a self contained fish farm or are tested for KHV AND SVC before you purchase.  Ask and only deal with reputable dealers.  If they don't quarantine, you don't want their fish.  

Don't forget that anytime you do a water change (if you are on county or city water), you will have CHLORINE in your watergarden, and you should add stress coat or another type of dechlorinator.  If you have to add water due to evaporation.....don't forget you are adding chlorine.