I got some kuhli (coolie) loachs a few weeks back. I dropped them in a 10-gal that I had cycled with four croaking gouramis. The loachs died within two days. They had trouble breathing and were unable to right themselves when flipped. I moved one downstairs to my 29-gal but it did nothing. In the morning it was dead. Upstairs I found another dead one. And a day later the last one. The ph was 6.5 temp was 80F and there were no nitrites is this the cause of gill flukes or what?