I have a 40 gallon tank that came with two goldfish when we bought our house. Six days ago, after a year and half, I added two more goldfish. After a couple days, the two original goldfish were covered in white dots. Is this ich? Their behavior still seems normal. Also, one of the new fish started out all orange and has been turning dark purple/brown. I brought a photo to the store where I bought the new fish and the guy said it didn’t look like any disease he’s ever seen. I appreciate any advice!