I've had goldfish in my pond for a couple of weeks. One of the apricot blush comets is developing black spots on its side. Is this a disease or a natural color variation. I've moved the fish to one of the pools on the stream so it is a little away from the other fish. I don't currently have a water testing kit, but I will be picking one up tomorrow. The pond is fairly new, has a 12 foot long stream and waterfall, a 4 x 8 foot bog garden planted with irises, papyrus, cat tail and some trailing red water weed. The water is crystal clear but I am getting a little algae growth on the rocks of the stream. Thanks for the help.