When you talk wriggly that usually means mosquito larva.
Look here
http://www.nlm.nih.gov/medlineplus/e...pages/1249.htm
But when you say they are holding on in a strong current that usually means
black fly larva.
Look here http://www.rayswords.com/bugs/pages/31b.htm
Leeches, if you pick one up, are soft. Insects, larva and adult, have hard
'skin', actually an outside skeleton to hold their innards together.
Look here for leech pictures
http://www.rackelhanen.se/eng/10143.htm

Not all leeches will latch onto you and digest blood. Some leeches eat the
decaying stuff
(detritus) in the pond. I've kept leeches, found in ponds, indoors with aquatic
frogs and snails and all the leeches do is rummage around in the rocks looking
for dead bits of plants, frog and snail poo.

All that being said, any one of these critters make excellent fish food. The
way to test leeches (barring offering them your finger) is to buy some liver
and put the leech in with the liver piece. Detritus eating leeches will turn
their noses up at liver.



kathy :-)
A HREF="http://www.onceuponapond.com/"Once upon a pond/A