I noticed today on one of my tetras fins a couple white marks. They seem to have appeared over night pretty much. There might have been very light marks there before but not this big. I've attached a couple pictures so everyone can see. The marks are on it's tail and pectoral fins. Also none of the other fish are showing any signs of white marks anywhere on them. Now some background on my tank...
Stocking is 5 black widow tetras, 2 swords and a few cherry shrimp. The cherry shrimp are the only thing that's changed in the tank in teh past 2-3 months. I got them 2 days ago from a very good LFS that has clean water knowledgeable staff.
Water changes atleast once I week of about 40% sometimes two 30% changes.
ammonia 0-.25 I always have trouble reading this one, nitrite is 0, and nitrAte is around 1-2 ppm.