Common Pond Snail Or Bladder/tadpole/pouch Snail

[br3ach]

I have looked at the thread here:

[URL="http/www.fishforums.net/index.php?showto...54&hl=snail"]http/www.fishforums.net/index.php?showto...54&hl=snail[/URL]

and I definitely have one or the other but I can't tell which. Are either a problem?

Thanks