Not sure what this is, but 3+ year old Glofish danio has growth on stomach area. I tried to take pics, but fish is very fast, eating/behaving normally. It doesn't look like a fungus or infection to me. Hoping someone can help with the ID. A/Ni=0, Na=15-20, pH=6.4-6.5. 72-73 degrees 5 gallon planted/filtered tank.