It seems that every yard is different. Do you have an issue with racoons now? Some people never have an issue, and others do. For bird related issues, some folks have netted their ponds. My yard is fenced, and I've only had minor issues. Last summer, something got ahold of one of my koi (she was probably 9-10" at the time) and left a hole in her face, but she got away. That pond has no shelves (this was a space issue, I wanted max water volume), measures about 11 x 18 with the max depth sloping down to 5' ... upper pond is 8 x 18, with depths as shallow as inches (due to gravel, supposed to be a bog), with the deepest spot (for lilies) being close to 3' ... Either late last fall, or early winter, we found a shubunkin out of the pond with vertical scratches (possibly claw marks) and over the course of the winter, lost a handful of comets and shubunkins (no bodies found) ... The next pond going in (20x25 liner) will be close to 3' and no shelves, but this is being built for all of hubby's lilies (although I have young/small koi that will use it for awhile to grow out in) ...bean6924 said:How important is it to not have shelves? I sort of need them because there is a conduit line preventing me from digging deeper in one spot (you can see the shelf in my original pic above). I know predators are a problem, but my property will be fenced in (hopefully keeping racoons out). Herons would be the only threat. I like the idea of a shelf aesthetically, but if predators are that big of a threat I can just dig much deeper and narrower.
I just met a gentlemen last week who stopped by as someone told him we had koi for sale. He lives about 10 minutes away, and says something cleaned out his pond over the winter. Didnt see it, but said he had nearly as many koi, and in the same size ranges as ours. We have about 30 koi outside ranging 7-8" to 23-24" ... He bought two babies that were in the 7-9" range ... He wants to give them a week or so. If these two dont get eaten (I hope not!), he is coming back for 3 larger fish.
There are other folks who have never had an issue.