A friend of mine gave me about 40 small 1-2 year old koi and 1 large 10+ year old. I've never kept koi before but was thinking about putting them into a spring fed pond on the property. There are currently no fish in the pond, it is about 4 feet deep, and 60 - 80 feet in diameter. Anyone have any experience with koi? Will the cool water not be good for them? Can I do anything to help them evade being eaten by the otters/herons? I have another pond, not fed by a spring that is roughly 2 acres in size. Right now it is loaded with crappie and catfish. Would the koi be better off in there? Will they negatively effect the pond or fish that are all ready in there? If koi are something to avoid let me know, I won't have any problems using them as catfish bait.