Betta & Swollen Eye

[commoncarp]

Tonight fed my fish only to discover my Bettas Eye is swollen really badly,looks like its going to pop out of his head... he was okay yesterday??? The tank has been cycled for a year, someone please help, what is this, do I need to treat the tank, shall I clove oil him, dunno what to do?

Thanks

Common Carp

 

[commoncarp]

An update the water is clean in the tank do about x2 water changes a week, I did a large water change yesterday and the fish was okay. I have some Melafix and see it treats swollen eyes (popeye) should I use this or just do %30 water changes everyday? I don't really want to poison my tank with Meds if I can help it. The Betta is still eating and does swim around occasionly, his normally kinda lazy anyway, just attacks a few platys when there near his territory.