Here in Kansas, White Perch are a nuisance specie and you can get fined for having live white perch. A lake about 15 miles from me has them and they are EVERYWHERE. The walleye and stripers are getting huge from eating them, but the walleye and all other fish will start dissapearing. The white perch will eat all the eggs. You really have trouble fishing for anything else, because everytime you cast you catch a white perch. I would say keep them out of your pond unless that is all you want in it.