Thanks for the extra confirmation Wetnwild
It wasn't my pond sadly but a friends of my boyfriends - oh, and it was just a small pond - errr...50mtrs across!

but his kids had been playing in the water and he was concerned a wee bit by the 'worms'
Seems there's big issues with the foresaid pond (owner says it's stagnent

) and I'm hoping to go see it for myself in the next few days, so brace yrselves for some questions shortly - think I'm gonna need some expert WAB help ok!!!