Sorry to reply so late - My water params are all perfect, i'm doing a 50% water change every other day, and no other fish have exhibited the symptoms of the oto and loach that died. I recently got the loaches and otos, but i've had the corries for a while. I've also just had an Ich outbreak that I've been trying to fight with heat to no avail, i raised the temp to 89º F (That was as high as the temp would ever get in the tank with my heaters cranked) and the ich only got worse, I maintained it at that temp for over a week and then the last day of the week the ich all of a sudden was REALLY bad and all over my discus so I gave in and added salt, I don't like to because my plant's hate it (Especially my star grass) But it is clearing up nicely now, i'll soon be lowering my temp back to around 83º F
The discus that was beat up is recovering very well, his fins are almost back to normal.
And I'm not sure how to describe the "spazzing" of the fish that died.... It was almost like an extremely violent seizure