I have 3 bala sharks in a 4 by 2 foot tank, Last night one of them started acting crazy swimming into things and jumping out of the water and then began swimming upside down, this morning it died, I assumed that it was just a random thing as I have not previously had any problems however I did a water change and added conditioner to the tap water that i replaced. This evening I have noticed that my other 2 bala sharks began acting in the same way - swimming into things and jumping out of the water, and I have noticed that some of their scales are falling off now. There are no spots or any other signs that relate to any diseases that I have looked at, however one of the two's eyes have gone cloudy and he has began to swim upside down. Also the other fish seem fine, although fairly quiet because I think my sharks are bothering them. Is there anything I can do to treat them or save the other one before he does the same thing I have tried putting in stress coat and have checked them regularly, and I am sure that no other fish would attack them as I have only got Clown Loaches, plecos and was planning on getting some others as I have recently changed from keeping malawi cichlids - which I now have in a new 6ft tank and nothing new has gone in? The pH of the water is 6.5 Temperature of 26 C Chlorine is at 0.2 ish NO3 is at about 50 NO2 is a bit above 1 and less than 5 (2or3 i think) GH is 16 KH is 3 PH 6.8 Thanks for any help that anyone may give.