So, one of my mollies developed a red sore on one of her gills. I've kept the water tested and kept everything up. Been having a massive problem with algae in the tank. Just resorted to chemical treatment of it. that one was a hard choice to make. But the smell of that stuff and the stubbornness of it..phew. Anyhow, for the past 2 1/2 weeks one of my oldest females has had a red sore on her gill. Now I haven't had any major nitrate spikes or anything so I'm honestly not sure what has caused it. This started before my recent problem with the algae. I've kept her with the family for this time period and seen no spread of it, so i don't think it's an infection. She isn't acting any different, but it still raises a concern for me.