My pond (preformed 100 gallon) has been set up for about 3 weeks now. I have 2 small koi I want to put in. Right now they are in a 10 gal tank inside. Our temps have been in the mid 30's at night and mid 50's during the day. I know that koi can take cold water but I am not sure how warm it should be after keeping them inside. Any suggestions on when I can put them outside. The pond was previously set up for 2.5 years and has water celery and some algae left from the move. The Koi came from the pet shop and have never been outside.