I have a small wildlife pond that has become home to a mutitude of leeches. Every year I get loads of frogspawn but not too many little frogs and I'm wondering if the leeches are killing the tadpoles etc. How do I control the leeches without harming the other residents?

There are many species of leeches. Most of them subsist on detritus, sure to be plentiful in a natural-type pond. They eat dead and dying plants and animals. A few species of leeches suck on fish and perhaps other aquatic animals. If you find your leeches hanging out in the debris and not sucking on animals, they are probably the first kind of leech which is not a threat to fish, tadpoles, or frogs. They may however eat the eggs perhaps.

How big is your pond? If it's small, the tadpoles will eat a lot of their siblings. I have a 153 gallon pond where probably 1000 wood frogs hatched a week ago and now, I can't find but a few. The other animals I have in there might have eaten a few but there's no way they ate all those so I don't know what happened to them either!

Leeches can be killed a number of ways. You can hang a piece of meat in the pond which will attract them which you then toss out. You can add fish "medications" but I don't know of one offhand that wouldn't also be detrimental to the tadpoles. If you want to go that route, I would wait until the tadpoles for the year have left. If you have multi-year developing tadpoles like green frogs, bullfrogs, etc., you'd have to clean the pond out and hand pick them out (which I've done on my ponds; it takes a LOT of time).

My suggestion is unless you see the leeches actually sucking on the frogs or tadpoles, assume they are not a problem. If there are so many that you think they are eating the frog eggs, you might want to put some eggs in another small pond (any non-toxic container), at least until they hatch and then move them back. The cleaner the pond is, the fewer leeches you'll have (but also less food for the tadpoles).

Good luck!

Robyn,
Many thanks to you.
Ian
PS a great site, I've loved pond dipping since I was a little boy and collected anything and everything into an old zinc bath tub in the back yard.

My pond is approximately 28 by 15 ft with a 6 ft waterfall. We have many leeches. Some of them are clearly carnivores because they attach themselves to me...legs and hands if I dig around in the rocks. I also have a healthy blue gill and four or five frgs...they seem fine, but the leeches are a deterent to the humans who like to get in and cool off. Would the meat idea help with this? Do I have to assume that they will eventually harm the reptiles and fish? They seem to be increasing in numbers and I find many in the filters. Thank You...I love your site.

The leeches that I have in my ponds live mostly in the filters (where fish can't get to them). They will sometimes stick to whatever they run into which means just because you find one stuck to you doesn't mean they're a blood sucker unless they've actually imbedded their mouths into you. If that is indeed the case, using meat bait to collect them will help.

Here's a few sites on fish leeches and control:
http://www.anglersnet.co.uk/authors/bruno10.htm
http://www.exotictropicals.com/encyclo/fre...ses.htm#Leeches

Clout kills leeches but can be dangerous for all invertebrates:
http://www.drsfostersmith.com/product/prod...24&js_enabled=0