Leeches?
Hi, I have a small pond, approx.900 gallons, with koi and goldfish. I noticed when I was cleaning the filter that there was small little reddish-brown “worms” but I don’t think they are worms because they can hold onto the filter when I try to wash them off. I caught a couple of my goldfish to see if they had any attached and they didn’t. I didn’t try any koi because I didn’t want to stress them. Do you think they are leaches and if so are they harmful? Thank You Sarah
