My fish has one red eye

[KMiller]

I was wondering if the reason my fish has a red eye is because the water still has chlorine even though i dechlorinate it. My pond is 125 gallons. I have plant life growing...elephant ears and lily pads (not sure how elephant ears started).
I believe my fish is koi (all white). My fish is 10" long.
I notice on occasion it gets a red eye. Any suggestions about how to treat the red eye? Is my fish okay?

 

[Gemma]

and welcome to GPF!
I'm not sure what causes the red eye, but could be due to the size of the pond.... 125gls is not a suitable pond for even one koi

 

[j.w]

@KMiller Time to start digging as that's a pretty large fish you have there. He may get even bigger and would love to have more room to swim.