Any opinions as to whether or not having leeches in your pond is good or bad? We have a very small variety in our pond, 1/2" in length, dark gray, with two black stripes running down it. Every summer there is about 6-8 week period where almost every LMB has several leeches attached to the inside of its mouth. When it starts to cool down the leeches disappear and the LMB mouths start to heal up rather quickly. I am not real concerned about it but thought it might be interesting to discuss the pros and cons of having leeches present in the pond with fish.