My Oscar is blind as well and I don’t know why some of my fish are going blind. Could it be somthing in the water? Or maybe they swam into somthing, I don’t think that’s the case because the big hit does swim very fast. It doesn’t make sense I don’t want it to happen to any more fish. Have any of you experienced somthing similar? My Oscar went blind months ago and no other fish was effected. I recently moved the bichir into the 220 and now he lost both his eyes.