One of my rays has had these little white bumps and filmy areas showing up around its eyes for a few weeks now. Hard to explain, so here is a picture. I'm guessing its some type of fungus. Since I'm am no expert at diagnosing fish health issues, I opted not to medicate without knowing what it is. I have upped my water change schedule (70% every 4-5 days) and added the recommended dose of aquartium salt (per directions on box) during these water changes. I didn't change the temp at all, it is still at 82F.
Amonia- 0
Nitrite- 0
nitrate- up to around 20ppm(30 if I've been feeding heavy) before water changes
The water is hard.
I don't have a test kit for ph and hardness now, but it should be pretty stable with all the water changes.
The other ray in the tank is not showing any signs of this at all.
Both rays are still very active and eat like there no tomorrow twice a day.
Any ideas on what it is and a treatment if needed?

Amonia- 0
Nitrite- 0
nitrate- up to around 20ppm(30 if I've been feeding heavy) before water changes
The water is hard.
I don't have a test kit for ph and hardness now, but it should be pretty stable with all the water changes.
The other ray in the tank is not showing any signs of this at all.
Both rays are still very active and eat like there no tomorrow twice a day.
Any ideas on what it is and a treatment if needed?
