55 Gallon Tank Betta eye changing solid colour (I don't think it's popeye)?

Not sure what's going on with my female koi betta. She always had one black eye, one white ringed eye. Then the ring slowly started filling up her eye. The eye with the white ring does look like it's a bit bigger than the black eye. I have started daily 30 minute epsom salt baths but I'm not even sure if this is popeye or not..? s she just changing colour? I know koi bettas can change colour sometimes.

Maybe it's a tumor? I hope not.

Water parameters:
Ammonia: 0
Nitrite: 0
Nitrate: 3
Temp: 79F
Tank size: 55 long

 

Eyes don't look swollen like popeye or a tumor at least.

 

Eyes don't look swollen like popeye or a tumor at least.

Do you know what would cause her eye to fill up like that? it use to be black with a white ring around it. then it developed a slant, like she looked angry type of look, then it just got more filled but very slowly.

 

Do you know what would cause her eye to fill up like that? it use to be black with a white ring around it. then it developed a slant, like she looked angry type of look, then it just got more filled but very slowly.

May be a natural thing. All my betta eyes have always started out black so have no experience with that myself. Might be worth checking out. Of the fish is acting and eating fine, i wouldn't worry about it terribly much though.

 

Well after doing a few days of salt baths, she's behaving better (swimming more) and she does eat, but her eye is def getting bigger..