Koi Fish in Distress

I have a big Koi Pond (approximately 3500 gallons, with clear water, only six adult Koi and eight little Koi). Lately they are schooling together, and a couple of them seem to be sucking for air.  Help, any answers? -Larry

Your pond may need more aeration for your Koi fish.  If the oxygen levels in your pond are low, the largest fish (the ones that need more oxygen) with suffer first.  Adding an air pump and an air stone will help bring your oxygen levels in the pump for the Koi fish up.