Urgent What the!!

Hi forum, as many of as do, i was looking into my tank to have a look at some night time viewing and i couldnt help but notice all these weird and wonderful creatures that come out only at night. they are all the usual things you would find. bristle worms, feather dusters etc.. but one suck out the most probably because it was swimming all around the light... i have managed to catch it and have it in a holding cup for these creatures.. i was hoping you guys could tell me what it is via my description because my camera cant focus on this small and swift thing!!

its about one center-meter long and it is a vivid aqua colour
thats it really thats all it looks like a piece of aqua coloured string that has a mind of its own

 

try to take a pic of it....and continue describing.

 

this thing it was to fast to take a picture of. if you want a picture you could basically draw the dam thing. haha.to me it looks like a aqua coloured ribbon worm to be honest but i think its way to short and small...

 

ok just had a look at ribbon worms and its definitely not that!

 

amphipod?

 

It's probably an epitoke. When bristle worms reproduce, a portion of their body changes shape. After a while, it pulls off the back of the worm, then swims like it is on crack to the top of the water column and then explodes or melts sending gametes into the water column.

 

Very interesting, had no idea about that.

 

The stuff that Inwall pulls out of his head just amazes me sometimes.