Just got a new ray in the q-tank a couple days ago and now during my daily water changes, there seems to be really really small brown roundworms in my tank. At first I thought it was just broken up poop, but then when I took a closer look, they are obviously moving around. I tried getting one under the microscope but its been impossible to actually pick one up as they're so damn small. They're like 2-3mm long and like 1/2mm thick. They do not look anything like planaria, nor do they look like flatworms. They're brown and round. Any idea what on earth this is? Harmful? Sorry, no pics, my camera cannot capture something this small...