Lots of skimmers come with that mod already -- but the hole is drilled in the bottom of the collection cup. Because skimmate tends to thicken as it sits, I think you'd be better off drilling it in the bottom vs. the side. I think it would clog too easily on the side, or it just wouldn't flow.
That's so fing stupid. Fish wont damange anything like a dog or cat would.
Unless you are David's fish!! :shock: