Hey everyone just observing my stingrays at night and I noticed from time to time they do this sneezing/gagging looking action. Like they curl up and looks like they want to gag or sneeze. Is this normal behavior or should i be worried about something? They don't do it always but I've seen it happened before. My parameters as of now is 0 ammo 0 nitrite 30ppm nitrate. Doing my water change tomorrow as my schedule routine for it is every Sundays.