I had a learning experience a couple of winters ago with my Koi(had them 8
years at that time). It was early January 4 degrees F outside. I always
bi-pass my bio/veggie filter over the winter and have a good hard stream of
water going directly into the pond from the pump. When the water starts to
ice over(maybe for a week or two) in January the forceful stream keeps a
hole open in the ice. Anyway....I hadn't check on the pond in the morning
like I usually do(to darn cold outside!!!) , my daughter happened to be
going outside and I asked her to check on the pond. This was in the early
evening before sundown. She came running into the house saying the pond was
almost dry and the backs of the Koi were up and out of the water. I ran
outside in disbelieve. Sure enough the hose for the stream of water had
slipped and almost all of the water had drained from the pond(4 degrees F
outside). My garden hose was frozen so I ran to my brother in laws about 3
blocks away that keep his garden hose in a heated garage. I ran
home....threw some antichlor into the pond,hooked the hose up and started
filling up the pond. Never phased the fish one bit...the survived the
ordeal fine. No sickness..didn't lose one fish. {:O) KOI are VERY HARDY
and ADAPTABLE. Mike