I now have three Kuhli Loaches, all of which seem extremely hardy and have survived when conditions were...well let's say "unfit". I have now maintained my tank with a pH of 7.8 and have stabilized my Nitrates and Nitrites...however, I used to have four Kuhli Loaches. About a week before it's death, my Kuhli started doing crazy things. It wouldn't stay nocturnal at all and it kept swimming all over the place darting around and acting real off balance and such. Could it have been swim bladder disease? However, I'd like to note it had a damaged eye that it could no longer see out of (I did a test by waving my hand next to the tank when it's bum eye was up to the glass and then did it with the other eye later (which it responded to). I'm not sure whether one of my other fish got to the eye, or it was apart of the disease that eventually killed it. I was really sad. I love my loaches, I think they're really neat looking. Also, I want to note my loach also would randomly stop moving after his spasms and drop to the bottom and lay on his side or in odd positions around the tank. I hope someone can help me diagnose the problem in the event that something similar happens again!