I have a planted 10 gallon tank, with a eco-complete substrate. I noticed a few weeks ago that there were some small green structures on a pebble in the substrate but figured the otos would take care of it. Now I'm seeing another one on the glass of the aquarium itself. They look like lttle green coral polyps and I'm noticing some all over my dwarf sag as well. Can anyboy tell me what these are and if they are a threat to my fish, or even to me?