I have a Australian rainbow that look like it has a gold dust on it and it has developed black lines going down its side and some black dots on its gills it is not rubbing and is active and eats but I am still concerned that it might be velvet. I also have a cherry barb, corry, Dalmatian molly, and a bumblebee catfish. I do not know mush about fish diseases and natural coloring of fish. So If someone could tell me if there is something wrong with my fish it would be great appreciated.