Two years ago the guy who built my renovated my pond decided it needed to be cleaned. And it did. So he took the fish out, emptied the pond, cleaned it, filled it back up, and put the fish back in. They all died. I had five koi various sizes and about 30 to 40 various kinds of goldfish. He replaced the koi with 4 quite large koi, big enough that our local heron sits in the adjacent tree but won't bother the koi, we even had an eagle scoping out the pond from the herons perch. Still have 4 koi. I have two labs which act as a deterrent when we're here, but we are away quite a bit. Koi are still swimming happily around the pond. I do have a couple of caves they can shelter in and in the summer, plenty of waterlilys. Last fall, we noticed with some surprise, about 30 small fry koi swimming around. Since there are no other fish in the pond they have to be koi. They're still there this spring, and it may be my imagination, but they look a little bigger. I think they're past the stage of being eaten by the big guys. What do I do now. My inclination is to leave them alone, as the had no help from me to get there in the first place. I'd be interested in any comments from you experienced pond owners as to your experiences.