It is awful to watch a fish suffer and get abused. You can learn from this however and follow up with better marine tank husbandry. Read about the habits of fish before you put it in with more passive fish. I learned after all these years that you can not always believe everything you read , and there are discrepencies. I put a six-line wrasse in my well established, 8 yr. old tank and it has blinded the other eye of my Royal gramma. It did fine with one eye until the wrasse entered the scene. Could be because the gramma was already blind in one eye. They are both very territorial. Gramma was very aggressive towards others when they entered his territory and that is how he lost his first eye. I am mortified!! He just went after it until the gramma has disappeared into the crevices of the rocks. Have attempted to get him out but impossible. Can not get the gramma out either. You never stop learning,