Ok, so for those of you that do not know my setup, 55 Gal tank, 2 Bala sharks about 4 inches long, 2 plecostomus between 4 and 6 inches long, and 2 Pacu about 1 foot long a piece (small tank, I know). Anyways, Woke up wednesday morning, my 2 plecostomus were dead, no sign of anything on the...