NEED HELP -- WEIRD EYE IN FISH

[nicole.]

Update: I got the maracyn and epsom salt and added it to the water he was in. Unfortunately little guy didn't survive ):

How do I prevent other fish from getting Popeye?

 

[kno4te]

Update: I got the maracyn and epsom salt and added it to the water he was in. Unfortunately little guy didn't survive ):

How do I prevent other fish from getting Popeye?

Not too much for already established fish but keep nitrates below 20ppm or low as possible. Quarantine for any new fish.