Pond full of leaches - is this a problem?

[hitchhiker 10]

My pond (2m x 1m x 0.7m deep) seems to be full of leaches. I've never seen this before and I wondered if it's normal!?! Should I introduce some fish who'll eat these leaches?

[cheekymoog 10]

Mine too this year, which I haven't seen before. It's a similar size to yours as well. I don't know whether they are good or bad though, sorry!

[quisquose 10]

My pond (no fish) always has lots of leaches in there, under the leaves that fall in.