Well right now i currently have 3 rbs in a 75gallon tank. I am having a problem with 1 eye willy.."the piranha with the missing eye from a long time ago", he is currently about 3 or 4 inches and showing some nice color but lately he has been gettin knipped hard on his fins now for the last 3 days he is up in the front corner of my tank just swimming there and always leaning like he is in danger. About 3 weeks ago i treated my tank with the fizzing parasite tablets just for saftey and followed all instrutions that go with them. so my question is my smallest 1eye willy just hiding from the other 2 very agressive piranhas or could he be ill with a interal parasite or fungus. I see no signs of any disease on the out side of his body or any of my other guys. My water temp is at 82 degrees and i have not changed it in any way and the only param i can post up is my PH and it is currently at 7.5_7.8......and he is eating normal when i feed him individually."peeld raw shrimp"......Please help any input is appreciated.