I’ve had my peppermint shrimp about 6 months. I have about 5 or 6 hermits that were with me from the moment my first tank finished cycling. I suppose it’s possible there could be some hyper trace amount of CU but I would think the peppermints would be showing signs of stress. I’ll see about getting a test kit for CU however. I’ll get the Hanna checker for CU once I can afford it but for now I’ll get a normal kit.