What Is This

[matthewkeogh50]

https/s.yimg.com/hd/answers/i/9ab05fc4313b404bb0f9afcccfba18d0_A.jpeg?a=answers&mr=0&x=1388520965&s=69a00c21a8ae2a8a5d36e4111e10b62d
 
this is not in my tank btw just helping some one out by trying to identify it 

 

[l_l_l]

You can refer to that post!
 
http/www.fishforums.net/index.php?/topic/277805-hitchhikers-in-freshwater-tanks-ponds/
I don't see pictures from this computer but I think I've seen it there..

 

[fish48]

it is a Demsalfly larvae. not really dangerous however it will eat very small fry