In both my planted tanks small leeches are appearing. Probably a max of 3/4 visible on the glass at any one time. The tanks contain only shrimps and ottos, so nothing to predate on them. They appear as either a small blob, or half inch long when travelling across the glass. Initially only came out when lights went off, but now are getting hard faced and appearing throughout the day. Im not to concerned, is it right for me to to assume they are harmless. Occasionally its possible to crush them on the glass if your quick, but usually they shrink on contact, and float away in the water current. Does anbody else have them.??????