I'm extremely bum lost all seven of my yoyo loaches. Four days ago I did my normal weekly 60% water change but decided to change out my powerhead aquaclear 70(400 gallon a hour) to a marineland(290 a gallon a hour) power head should have notice something is up when I notice a lot flake food on top the gravel. I feed even less then normal with aquaclear 70 it pretty turbulent but gravel water is always clear, with marineland at a lower rate there was lot flake on gravel top. Woke up this morning foond one loach dead and upon looking around whole tank I found all seven dead!! Did quick 60% water change, everyone else is doing great so far! The survivors are four blood parrots, three spotted raphael,three stripe raphael, two feather fin catfish, two warmouth sunfish, and two blue spot gourami. Could a sudden ammonia spike from lower circulation seal my loaches fate?