Thanks! I did get a reply from some local folks, and the lantana is apparently not a problem if the flowers blow in the pond. No wild areas nearby, I'm in the city, and there's plenty of wild lantana growing here anyways! It's a pretty plant, and tolerates our Texas heat and drought very well. (I love weeds, and am not particularly sensitive to this one...some people get irritating rashes from handling the thorny stems, but I don't. Wouldn't eat 'em though, and will keep them away from the dogs' pen. They smell nasty, so likelihood the dogs wouldn't eat 'em anyways. Had lantana in my last yard, and the dogs left it alone. Bloomed pretty much all year except the coldest part of winter.
I'm gonna be trying to remove the babies and give them away, but catching the little buggers is an issue! They're quick! In a pond this size (180 gallons) I figure I really should only have about 3 goldfish, plus the minnows. Of course, the goldfish have other ideas...