One of our Tetra's just came down with white around his mouth, base of the caudal, dorsal and one of the pectoral fins. We move him to a hospital tank. Our DT is 29gal, pH7.6, 78 degrees, Nh3-0, No2-0, No3=5-10ppm.Water change done 6 days ago, 50%.There are 6 Platys, 8 Glolight Danios, 5 Panda...