I have a saltwater tank with 2 clownfish (I've had them for 4 years), hermit crabs, cleaner shrimp, live rock, and an anenome. One of the fish has a raised white spot about the size of grain of sand on his side. I noticed it about 3 days ago, but it's so small, it could have been there longer. The fish is very active and eating fine. The salinity is currently 1.023 - 1.024 and the temperature is 78. No measureable amonia or nitrite. What should I do? I don't think that a copper treatment is an option since I have invertabrates. Should I change the salinity or temperature - is there another type of medication.