Hi, I have been finding these little things in my tank ever since I got it 5 months ago. Does anyone know what it is? It looks kind've like a popcorn kernel. They've ranged in size from this smiley to as big as a pea. Will they grow? is it anything plant related? I know that it hasn't come from any plants in my tank because all I have is a java fern right now, and I've been seeing these since before I got it.